8.16.1 Release notes

[nastasha-solomon]

Adds 8.16.1 release notes and makes the following changes:

• Removes the breaking change that was reported in 8.16 since it's more relevant to Kibana.
• Adds a resolution date and recommendation to upgrade to 8.16.1 for the following known issues that were reported in 8.16.0:
  • Alerts page crashes if you upgrade to 8.16 and access it in a non-default Kibana space
  • Attempting to edit an Elastic AI Assistant Knowledge Base index results in an error

Previews:

• 8.16.1 release notes
• 8.16.0 release notes

[github-actions]

A documentation preview will be available soon.

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[mergify]

This pull request is now in conflicts. Could you fix it @nastasha-solomon? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b rn-8.16.1 upstream/rn-8.16.1
git merge upstream/main
git push upstream rn-8.16.1

[benironside]

Two minor edits, otherwise LGTM!

[stephmilovic]

LGTM for GenAI changes!