[8.8] [ESS] Adds beta tag to D4C (backport #5519)

[mergify]

Adds a beta tag to the D4C docs

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This is an automatic backport of pull request #5519 done by Mergify.

[mergify]

Cherry-pick of 13eaeb0 has failed:

On branch mergify/bp/8.8/pr-5519
Your branch is up to date with 'origin/8.8'.

You are currently cherry-picking commit 13eaeb04.
  (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:   docs/cloud-native-security/d4c-get-started.asciidoc
	both modified:   docs/cloud-native-security/d4c-overview.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

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[benironside]

will fix these in a separate PR