Disable sync for offline cloud licenses

What does this MR do and why?

Part of https://gitlab.com/gitlab-org/gitlab/-/issues/349614

Updates seat link sync logic to prevent syncing if the current license is an offline cloud license.

Screenshots or screen recordings

Does not apply

How to set up and validate locally

I would think that reviewing and validating the specs should be enough for this case.

MR acceptance checklist

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