[8.10] docs: Clean up OpenTelemetry docs (backport #11882)

[mergify]

This is an automatic backport of pull request #11882 done by Mergify.
Cherry-pick of 691b526 has failed:

On branch mergify/bp/8.10/pr-11882
Your branch is up to date with 'origin/8.10'.

You are currently cherry-picking commit 691b5269e.
  (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:   docs/otel-direct.asciidoc
	modified:   docs/otel-limitations.asciidoc
	modified:   docs/otel-other.asciidoc

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   docs/otel-metrics.asciidoc

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

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[colleenmcginnis]

@elasticmachine, run elasticsearch-ci/docs

[colleenmcginnis]

@bmorelli25 I'm having trouble tracking down the error here. Can you please take a look? 👀

Oh gosh it was an unresolved merge conflict. 🙈