Ensure AI license and membership

What does this MR do and why?

Part of: https://gitlab.com/gitlab-org/gitlab/-/issues/407159

This checks if the group has a license for summarize_notes and makes sure that only users who are part of the group have access to the feature.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.