[8.x] [Serverless][8.17] Cases subfeatures (backport #6288)

[mergify]

Contributes to #6266 by updating the Security docs.

Previews:

• ESS - Updates the note in the row that describes priv reqs for users with view (read) only access.
• Serverless - Same changes

  ---

  This is an automatic backport of pull request [Serverless][8.17] Cases subfeatures  #6288 done by Mergify.

[mergify]

Cherry-pick of b445b87 has failed:

On branch mergify/bp/8.x/pr-6288
Your branch is up to date with 'origin/8.x'.

You are currently cherry-picking commit b445b874.
  (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/cases/cases-req.asciidoc

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/serverless/investigate/case-permissions.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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