[main](backport #43041) [9.0](backport #43029) [main](backport #42980) docs: Prepare Changelog for 8.17.3

[mergify]

Prepare Changelog for 8.17.3.

Merge once the BC that will be published is decided.

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This is an automatic backport of pull request #42980 done by Mergify.

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This is an automatic backport of pull request #43029 done by Mergify.

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This is an automatic backport of pull request #43041 done by Mergify.

[mergify]

Cherry-pick of 61a93f0 has failed:

On branch mergify/bp/main/pr-43041
Your branch is up to date with 'origin/main'.

You are currently cherry-picking commit 61a93f045.
  (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)

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

no changes added to commit (use "git add" and/or "git commit -a")

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