[8.5] Adds Allowlist Elastic Endpoint in third-party antivirus apps page to serverless docs (backport #5639)

[mergify]

Resolves #3433, which is a duplicate of #3535.

This PR adds the Allowlist Elastic Endpoint in third-party antivirus apps page to serverless docs and a disambiguation note to the Trusted applications page.

Previews:

• ESS:
  • Allowlist Elastic Endpoint in third-party antivirus apps
  • Trusted applications
• serverless: Click the preview link in this comment and navigate to:
  • Elastic Security -> Manage endpoint protection -> Allowlist Elastic Endpoint in third-party antivirus apps
  • Elastic Security -> Manage endpoint protection -> Trusted applications

---

This is an automatic backport of pull request #5639 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of f8e7ca6 has failed:

On branch mergify/bp/8.5/pr-5639
Your branch is up to date with 'origin/8.5'.

You are currently cherry-picking commit f8e7ca6e.
  (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/management/admin/allowlist-endpoint-3rd-party-av.asciidoc
	modified:   docs/management/admin/trusted-apps.asciidoc
	new file:   docs/serverless/edr-manage/allowlist-endpoint-3rd-party-av.mdx

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/serverless/edr-manage/trusted-apps-ov.mdx
	deleted by us:   docs/serverless/serverless-security.docnav.json

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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