[8.x] BYO LLM 8.16 updates (backport #5967)

[mergify]

Fixes #5965 — updates the bring your own LLM guide to reflect a change in the Elastic Integration configuration interface for OpenAI connectors.

Previews: BYO LLM (serverless version)

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This is an automatic backport of pull request #5967 done by Mergify.

[mergify]

Cherry-pick of 3d18f62 has failed:

On branch mergify/bp/8.x/pr-5967
Your branch is up to date with 'origin/8.x'.

You are currently cherry-picking commit 3d18f626.
  (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/AI-for-security/connect-to-byo.asciidoc
	modified:   docs/AI-for-security/images/lms-edit-connector.png

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/serverless/AI-for-security/connect-to-byo-llm.mdx
	deleted by us:   docs/serverless/AI-for-security/images/lms-edit-connector.png

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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