elastic#87914)

## Summary

Changes `DELETE` to `POST` for _bulk_delete on the client only for a variety of reasons.

According to the RFC, not all servers and proxies need to honor DELETE having a body. From: https://tools.ietf.org/html/rfc7231

```
A payload within a DELETE request message has no defined semantics;
sending a payload body on a DELETE request might cause some existing
implementations to reject the request.
```

Within at least one proxy, h2o2, we have found that it does indeed change request headers which will cause NodeJS to not attach the body of a `DELETE`:
hapijs/h2o2#124

Also from other communities such as OpenAPI where they debated this, they allow it but discourage it for reasons outlined there that I will not repeat here:
OAI/OpenAPI-Specification#1937

Elastic Search API's and other Kibana API's use `POST` rather than `DELETE` for their bodies that are attached to `DELETE`:
https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-delete-by-query.html

We still support bodies in `DELETE` and `POST` but are just changing the web client to utilize `POST` moving forward.


### Checklist

Reviewed and we already have unit tests and end to end tests for these use cases so we are good with just updating them. 

- [x] [Unit or functional tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html) were updated or added to match the most common scenarios

#87914) (#88509)

## Summary

Changes `DELETE` to `POST` for _bulk_delete on the client only for a variety of reasons.

According to the RFC, not all servers and proxies need to honor DELETE having a body. From: https://tools.ietf.org/html/rfc7231

```
A payload within a DELETE request message has no defined semantics;
sending a payload body on a DELETE request might cause some existing
implementations to reject the request.
```

Within at least one proxy, h2o2, we have found that it does indeed change request headers which will cause NodeJS to not attach the body of a `DELETE`:
hapijs/h2o2#124

Also from other communities such as OpenAPI where they debated this, they allow it but discourage it for reasons outlined there that I will not repeat here:
OAI/OpenAPI-Specification#1937

Elastic Search API's and other Kibana API's use `POST` rather than `DELETE` for their bodies that are attached to `DELETE`:
https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-delete-by-query.html

We still support bodies in `DELETE` and `POST` but are just changing the web client to utilize `POST` moving forward.


### Checklist

Reviewed and we already have unit tests and end to end tests for these use cases so we are good with just updating them. 

- [x] [Unit or functional tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html) were updated or added to match the most common scenarios

* master: (33 commits)
  [Security Solution][Case] Fix patch cases integration test with alerts (elastic#88311)
  [Security Solutions][Detection Engine] Removes duplicate API calls (elastic#88420)
  Fix log msg (elastic#88370)
  [Test] Add tag cloud visualization to dashboard in functional test for reporting (elastic#87600)
  removing kibana-core-ui from codeowners (elastic#88111)
  [Alerting] Migrate Event Log plugin to TS project references (elastic#81557)
  [Maps] fix zooming while drawing shape filter logs errors in console (elastic#88413)
  Porting fixes 1 (elastic#88477)
  [APM] Explicitly set environment for cross-service links (elastic#87481)
  chore(NA): remove mocha junit ci integrations (elastic#88129)
  [APM] Only display relevant sections for rum agent in service overview (elastic#88410)
  [Enterprise Search] Automatically mock shared logic files (elastic#88494)
  [APM] Disable Create custom link button on Transaction details page for read-only users
  [Docs] clean-up vega map reference documenation (elastic#88487)
  [Security Solution] Fix Timeline event details layout (elastic#88377)
  Change DELETE to POST for _bulk_delete to avoid incompatibility issues (elastic#87914)
  [Monitoring] Change cloud messaging on no data page (elastic#88375)
  [Uptime] clear ping state when PingList component in unmounted (elastic#88321)
  [APM] Consistent terminology for latency and throughput (elastic#88452)
  fix copy (elastic#88481)
  ...