[Fleet] Limit pagination size when retrieving full policy or withAgentCount

[nchaulet]

Description

Resolve https://github.com/elastic/kibana/issues/192178

As retrieving agent policies with all the integration policy or with agent count could have a terrible performance impact, that PR aims to limit the pagination to 100 agent policies when retrieving policies with those options.

Retrieving agent policies without agent count is no the new default behaviour and I introduced a new query parameter withAgentCount to retrieve the agent count

This will be a breaking change for 9.0

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[nchaulet]

@juliaElastic I changed a little my PR to make that breaking less brutal/risky for users the GET /agent_policiesnow do not retrieve agent count by default and I introduced a newwithAgentCount` parameter, I tested in depth our UI and nothing break.

[nchaulet]

@elasticmachine merge upstream

[nchaulet]

@elasticmachine merge upstream

[elasticmachine]

:green_heart: Build Succeeded

• Buildkite Build
• Commit: 7547eacd7235e6d9eef8fb8794093f1f775eb69d

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
fleet	1.7MB	1.7MB	+2.0B

History

• :broken_heart: Build #244349 failed 5998bfd2e0ffd4ede0f726f12f3d38babd6c0fd4
• :broken_heart: Build #244016 failed 7331d21b11707355d6248f66d9672ad79cef462f
• :broken_heart: Build #243962 failed f3de12aef95d1dde7e09d9e176cb98871e86e91f
• :broken_heart: Build #243896 failed 70872413c5e2c0ea8bce3c3039fefbc2c6233f30

cc @nchaulet