[8.16] Add known issue for orphaned status blocking upgrades (backport #1566)

[mergify]

As reported by elastic/elastic-agent#6213, if the audit/unenroll endpoint is used, agent status becomes inconsistent and certain actions, such as UPGRADE can no longer be issued to them through the fleet-ui.

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This is an automatic backport of pull request #1566 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 241d839 has failed:

On branch mergify/bp/8.16/pr-1566
Your branch is up to date with 'origin/8.16'.

You are currently cherry-picking commit 241d839.
  (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/en/ingest-management/release-notes/release-notes-8.16.asciidoc

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/en/ingest-management/release-notes/release-notes-8.17.asciidoc

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

[github-actions]

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