[Filebeat] Change okta.target to nested field (#24636)

* Change okta.target to nested field

* update to flattened field type

* fixed test files

* update changelog

* Move changelog line to Added section

Co-authored-by: Marc Guasch <marc.guasch@elastic.co>

CHANGELOG.next.asciidoc

@@ -818,6 +818,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Add `proxy_url` config for httpjson v2 input. {issue}24615[24615] {pull}24662[24662]
 - Add support for upper case field names in Sophos XG module {pull}24693[24693]
 - Add `fail_on_template_error` option for httpjson input. {pull}24784[24784]
+- Change `okta.target` to `flattened` field type.  {issue}24354[24354] {pull}24636[24636]
 
 *Heartbeat*
 

filebeat/docs/fields.asciidoc

@@ -112258,7 +112258,7 @@ type: keyword
 The list of targets.
 
 
-type: array
+type: flattened
 
 --
 

x-pack/filebeat/module/okta/system/_meta/fields.yml

@@ -62,7 +62,7 @@
       Display name of the actor.
 
 - name: client
-  title: Client 
+  title: Client
   short: Fields about the client of the actor.
   description: >
     Fields that let you store information about the client of the actor.
@@ -73,18 +73,18 @@
     type: ip
     description: >
       The IP address of the client.
-    
+
   - name: user_agent
     description: >
       Fields about the user agent information of the client.
     type: group
     fields:
- 
+
     - name: raw_user_agent
       type: keyword
       description: >
         The raw informaton of the user agent.
-    
+
     - name: os
       type: keyword
       description: >
@@ -133,7 +133,7 @@
   short: The list of targets.
   description: >
     The list of targets.
-  type: array
+  type: flattened
   fields:
 
   - name: id
@@ -275,7 +275,7 @@
   type: group
   fields:
 
-  - name: as 
+  - name: as
     type: group
     description: >
       The autonomous system.
@@ -291,7 +291,7 @@
       description: >
         The organization that owns the AS number.
       fields:
-      
+
       - name: name
         type: keyword
         description: >