[7.17](backport #39869) Migrate github checks to buildkite for libbeat and x-pack/libbeat

[mergify]

Proposed commit message

Migrate github checks to buildkite for libbeat and x-pack/libbeat

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Related issues

• https://github.com/elastic/ingest-dev/issues/3380

Logs

---

This is an automatic backport of pull request #39869 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 02a57f7 has failed:

On branch mergify/bp/7.17/pr-39869
Your branch is up to date with 'origin/7.17'.

You are currently cherry-picking commit 02a57f7648.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   .buildkite/x-pack/pipeline.xpack.libbeat.yml

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   .buildkite/libbeat/pipeline.libbeat.yml
	deleted by them: .github/workflows/check-libbeat.yml

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[botelastic]

This pull request doesn't have a Team:<team> label.