Refactored UserVisibilityMediator to use UserVisibilityType.

Test: atest FrameworksMockingServicesTests:com.android.server.pm.UserManagerServiceTest UserVisibilityMediatorMUMDTest UserVisibilityMediatorSUSDTest UserControllerTest

Fixes: 261537398

Change-Id: Ic4f15603cbfb63731ba32c5f2a9a3b9a6a17f214
7 files changed