[8.17] Add known issue for Elastic Agent failing to enroll into Fleet (backport #1801)

[mergify]

This PR adds a known issue to the release notes for releases:

• 8.17.1
• 8.17.2
• 8.17.3
• 8.17.4
• 8.17.5
• 8.17.6
• 8.17.7
• 8.18.0
• 8.18.1
• 8.18.2

Also fixes some typos.

Contributes to #1800

---

This is an automatic backport of pull request #1801 done by Mergify.

[mergify]

Cherry-pick of 26b645b has failed:

On branch mergify/bp/8.17/pr-1801
Your branch is up to date with 'origin/8.17'.

You are currently cherry-picking commit 26b645b.
  (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-8.17.asciidoc

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/en/ingest-management/release-notes/release-notes-8.18.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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