[ResponseOps][Rules] OAS schema registration for newly versioned Rule APIs

[adcoelho]

Summary

Issue: #187574

This PR updates request and response schemas below for rule APIs to generate OAS documentation:

• POST /api/alerting/rule/{id?}/_enable
• POST /api/alerting/rule/{id?}/_disable
• POST /api/alerting/rule/{id?}/_update_api_key

How to test

1. Start ES
2. Add server.oas.enabled: true to kibana.dev.yml
3. Start Kibana yarn start --no-base-path
4. curl -s -u elastic:changeme http://localhost:5601/api/oas\?pathStartsWith\=/api/alerting/rule/ | jq
5. Look for _enable, _disable and _update_api_key in the resulting JSON

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: e42b54d

Failed CI Steps

• FTR Configs #70

Metrics [docs]

✅ unchanged

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @adcoelho

[js-jankisalvi]

LGTM 👍

[umbopepato]

The requests show up correctly in the OAS spec, LGTM!