Summary: It's useless without SMS support and only exposed to the user themselves. Closes T15486 Test Plan: Before and after applying this patch, * Try to access the list of your contact numbers at `/settings/panel/contact/` * Try to access an existing, previously created contact number at `/auth/contact/1/` * Try to add a contact number at `/auth/contact/edit/` * Go to e.g. `/settings/panel/datetime` and check the "Authentication" section in the left sidebar for {nav icon=hashtag, name=Contact Numbers} Reviewers: O1 Blessed Committers, speck Reviewed By: O1 Blessed Committers, speck Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno Maniphest Tasks: T15486 Differential Revision: https://we.phorge.it/D25452