FirebaseAuthRecentLoginRequiredException is really tricky

[grodin]

FirebaseAuthRecentLoginRequiredException is going to be a real pain. It can be thrown on potentially any operation on FirebaseUser instance, and requires re-authenticating. The current structure, with authentication at (nearly) the root of the workflow tree means that we need to be able to jump down to there and return back to where we were.

This should only be of concern in the "Edit user account" screen, so perhaps has limited reach.