Add API endpoint to revoke PATs for service accounts

What does this MR do and why?

Add API endpoint to revoke PATs for service accounts

For the group services account API, allow to revoke personal access tokens.

I will add the documentation in a follow-up MR.

EE: true

Changelog: added

References

Closes #513959 (closed)

Screenshots or screen recordings

How to set up and validate locally

1. Enable Ultimate license on a group
2. Create a service account
3. Associate the service account with the group
4. Create a PAT for the service accounts
5. Revoke the PAT via the new API endpoint

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