Do not expose Contact Numbers settings panel when no SMS support configured

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 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