Use TextInputLayout for the name field in the create/rename mode page

In addition to looking nicer, this fixes two accessibility issues ("no hint when text is entered" and "reason for disabled button is unclear").

This requires a bit of theme merging black magic, because TextInputLayout requires a Theme.AppCompat descendant, which the Settings theme isn't.

Fixes: 356398157
Fixes: 370654542
Fixes: 369942776
Test: atest ZenModeEditNamePreferenceControllerTest
Flag: android.app.modes_ui
Change-Id: I92d8ec044dabc6daed5d755e206120ec7abc143e