Merge "Give each preference screen its own activity and toolbar title" into sc-dev am: 8d6ca68786 am: 750a30eaad

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14709732

Change-Id: I04c1a218d518f3c33eebed60f03524cc23478ed7