Replace StatusBarUserSwitcherController with UserInteractor

Originally, the user chip in the status bar was controlled by
StatusBarUserSwitcherController, which was backed by
UserInfoControllerImpl. This data source would sometimes show incorrect
data for the current user name.

Since UserRepository/UserInteractor exist now, this CL hooks up the
existing StatusBarUserSwitcherContainer view to a new class,
StatusBarUserChipViewModel, which is backed by the new repository class.

This allows us to fix 2 bugs at once:

1. The chip now only shows when there are > 1 users AND the config is
   true
2. Hooking the chip up to the same data source that populates the user
   switcher screen means that the names will always be consistent

Also removed the now-unused StatusBarUserSwitcherController, and its
associated feature controller and tracker classes.

Test: atest StatusBarUserChipViewModelTest
Test: atest UserInteractorRefactoredTest
Test: atest KeyguardStatusBarViewControllerTest
Test: atest PhoneStatusBarViewControllerTest

Bug: 254246505
Bug: 254680435
Change-Id: I3f5e212fed485b5697dedbe0510ab6c34d3b2ade