Allow users to access some settings at the "Add MFA" account setup roadblock
Tweak this UI to give users limited access to settings, so they can set up contact numbers and change their language.
(This is a little bit fiddly, and I'm doing it early on partly so it can get more testing as these changes move forward.)
Reviewed By: amckinley
Maniphest Tasks: T13222
Differential Revision: https://secure.phabricator.com/D20008