Deleting an authorized app (e.g. testing frontend) does not log out the client

Steps to reproduce

1. Spin up a frontend on a local machine for testing
2. Log in to a pod
3. Delete the authorized frontend in your user settings
4. Open up the frontend again

What happens?

The application stays logged in, but the refresh token can't be used so calls start failing.

What is expected?

If the app is deleted, the frontend should be logged out.

Context

Funkwhale version(s) affected: x.y

This caused testing issues in !2150 (merged) and !2149 (merged). I had accidentally deleted the app while testing something else and hadn't caught the issue because it was still logged in.