[Logs] Deprecate HTTP APIs used in LogStream app (elastic#201974)

## 📓 Summary

Closes elastic#200968 

These changes deprecate internal APIs used by the LogStream app, which
is also deprecated.

With v9, any internal API will become unreachable from external origins.
In case we get an external request to these APIs (although it should be
less likely to happen), the deprecation will be surfaced on the Upgrade
Assistant UI as a warning.

<img width="3005" alt="Screenshot 2024-11-27 at 13 16 39"
src="https://github.com/user-attachments/assets/c3864a5a-49c7-4cbd-8893-9041b5ee207e">

<img width="3007" alt="Screenshot 2024-11-27 at 13 16 25"
src="https://github.com/user-attachments/assets/f9fb254f-b795-4d01-8d92-463a0ca526a3">

Co-authored-by: Marco Antonio Ghiani <marcoantonio.ghiani@elastic.co>

x-pack/plugins/observability_solution/logs_shared/server/routes/log_entries/highlights.ts

@@ -12,6 +12,7 @@ import { fold } from 'fp-ts/lib/Either';
 import { identity } from 'fp-ts/lib/function';
 import { schema } from '@kbn/config-schema';
 
+import { i18n } from '@kbn/i18n';
 import { logEntriesV1 } from '../../../common/http_api';
 import { throwErrors } from '../../../common/runtime_types';
 
@@ -33,6 +34,20 @@ export const initLogEntriesHighlightsRoute = ({ framework, logEntries }: LogsSha
       {
         version: '1',
         validate: { request: { body: escapeHatch } },
+        options: {
+          deprecated: {
+            documentationUrl: '',
+            severity: 'warning',
+            message: i18n.translate(
+              'xpack.logsShared.deprecations.postLogEntriesHighlightsRoute.message',
+              {
+                defaultMessage:
+                  'Given the deprecation of the LogStream feature, this API will not return reliable data in upcoming versions of Kibana.',
+              }
+            ),
+            reason: { type: 'deprecate' },
+          },
+        },
       },
       async (requestContext, request, response) => {
         const payload = pipe(

x-pack/plugins/observability_solution/logs_shared/server/routes/log_entries/summary.ts

@@ -12,6 +12,7 @@ import { fold } from 'fp-ts/lib/Either';
 import { identity } from 'fp-ts/lib/function';
 import { schema } from '@kbn/config-schema';
 
+import { i18n } from '@kbn/i18n';
 import { logEntriesV1 } from '../../../common/http_api';
 import { throwErrors } from '../../../common/runtime_types';
 
@@ -36,6 +37,20 @@ export const initLogEntriesSummaryRoute = ({
       {
         version: '1',
         validate: { request: { body: escapeHatch } },
+        options: {
+          deprecated: {
+            documentationUrl: '',
+            severity: 'warning',
+            message: i18n.translate(
+              'xpack.logsShared.deprecations.postLogEntriesSummaryRoute.message',
+              {
+                defaultMessage:
+                  'Given the deprecation of the LogStream feature, this API will not return reliable data in upcoming versions of Kibana.',
+              }
+            ),
+            reason: { type: 'deprecate' },
+          },
+        },
       },
       async (requestContext, request, response) => {
         const payload = pipe(

x-pack/plugins/observability_solution/logs_shared/server/routes/log_entries/summary_highlights.ts

@@ -12,6 +12,7 @@ import { fold } from 'fp-ts/lib/Either';
 import { identity } from 'fp-ts/lib/function';
 import { schema } from '@kbn/config-schema';
 
+import { i18n } from '@kbn/i18n';
 import { logEntriesV1 } from '../../../common/http_api';
 import { throwErrors } from '../../../common/runtime_types';
 
@@ -35,6 +36,20 @@ export const initLogEntriesSummaryHighlightsRoute = ({
       {
         version: '1',
         validate: { request: { body: escapeHatch } },
+        options: {
+          deprecated: {
+            documentationUrl: '',
+            severity: 'warning',
+            message: i18n.translate(
+              'xpack.logsShared.deprecations.postLogEntriesSummaryHighlightsRoute.message',
+              {
+                defaultMessage:
+                  'Given the deprecation of the LogStream feature, this API will not return reliable data in upcoming versions of Kibana.',
+              }
+            ),
+            reason: { type: 'deprecate' },
+          },
+        },
       },
       async (requestContext, request, response) => {
         const payload = pipe(

x-pack/plugins/observability_solution/logs_shared/server/routes/log_views/get_log_view.ts

@@ -5,6 +5,7 @@
  * 2.0.
  */
 
+import { i18n } from '@kbn/i18n';
 import { logViewsV1 } from '../../../common/http_api';
 import { LOG_VIEW_URL } from '../../../common/http_api/log_views';
 import { createValidationFunction } from '../../../common/runtime_types';
@@ -30,6 +31,17 @@ export const initGetLogViewRoute = ({
             params: createValidationFunction(logViewsV1.getLogViewRequestParamsRT),
           },
         },
+        options: {
+          deprecated: {
+            documentationUrl: '',
+            severity: 'warning',
+            message: i18n.translate('xpack.logsShared.deprecations.getLogViewRoute.message', {
+              defaultMessage:
+                'Given the deprecation of the LogStream feature, this API will not have any effect configuring upcoming versions of Kibana.',
+            }),
+            reason: { type: 'deprecate' },
+          },
+        },
       },
       async (_requestContext, request, response) => {
         const { logViewId } = request.params;

x-pack/plugins/observability_solution/logs_shared/server/routes/log_views/put_log_view.ts

@@ -5,6 +5,7 @@
  * 2.0.
  */
 
+import { i18n } from '@kbn/i18n';
 import { logViewsV1 } from '../../../common/http_api';
 import { LOG_VIEW_URL } from '../../../common/http_api/log_views';
 import { createValidationFunction } from '../../../common/runtime_types';
@@ -26,6 +27,17 @@ export const initPutLogViewRoute = ({ framework, getStartServices }: LogsSharedB
             body: createValidationFunction(logViewsV1.putLogViewRequestPayloadRT),
           },
         },
+        options: {
+          deprecated: {
+            documentationUrl: '',
+            severity: 'warning',
+            message: i18n.translate('xpack.logsShared.deprecations.putLogViewRoute.message', {
+              defaultMessage:
+                'Given the deprecation of the LogStream feature, this API will not have any effect configuring upcoming versions of Kibana.',
+            }),
+            reason: { type: 'deprecate' },
+          },
+        },
       },
       async (_requestContext, request, response) => {
         const { logViewId } = request.params;

x-pack/plugins/observability_solution/logs_shared/server/services/log_entries/log_entries_service.ts

@@ -22,10 +22,20 @@ export class LogEntriesService {
     setupDeps: LogEntriesServiceSetupDeps
   ) {
     void core.getStartServices().then(([, startDeps, selfStartDeps]) => {
+      /**
+       * @deprecated
+       *
+       * Given the deprecation of the LogStream feature, this API will not return reliable data in upcoming versions of Kibana.
+       */
       setupDeps.data.search.registerSearchStrategy(
         LOG_ENTRIES_SEARCH_STRATEGY,
         logEntriesSearchStrategyProvider({ ...setupDeps, ...startDeps, ...selfStartDeps })
       );
+      /**
+       * @deprecated
+       *
+       * Given the deprecation of the LogStream feature, this API will not return reliable data in upcoming versions of Kibana.
+       */
       setupDeps.data.search.registerSearchStrategy(
         LOG_ENTRY_SEARCH_STRATEGY,
         logEntrySearchStrategyProvider({ ...setupDeps, ...startDeps, ...selfStartDeps })