Do not allow ci to Authorize with no actor

What does this MR do and why?

In the past we allowed ci to authorize without an actor.

This is no longer allowed but we left it around for backward compatibility. https://gitlab.com/gitlab-org/gitlab/-/blob/0df104f0c72ef838c5d2f5c04de4763cb3a73a79/lib/gitlab/auth.rb#L317

We have been logging for a few months if this code is ever hit and haven't seen any hits. !92935 (merged)

Now we can take the next step and explicitly ban this operation.

See the Issue for additional context around 'why': https://gitlab.com/gitlab-org/gitlab/-/issues/363711

MR acceptance checklist

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