[8.16] [ESS & Serverless] Adds OrganizationUnitIDs description to agentless section of AWS CSPM guide (backport #6155)

[mergify]

Fixes #5636
Adds OrganizationalUnitIDs field to the agentless CSPM AWS guides, edits the field's description in agent-based method.

Preview: CSPM for AWS (ESS), (Serverless)

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This is an automatic backport of pull request #6155 done by Mergify.

[mergify]

Cherry-pick of ed8b9bb has failed:

On branch mergify/bp/8.16/pr-6155
Your branch is up to date with 'origin/8.16'.

You are currently cherry-picking commit ed8b9bbb.
  (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/cloud-native-security/cspm-get-started-aws.asciidoc

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/serverless/cloud-native-security/cspm-get-started.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

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