Refactored Settings calls to removeUserOrSetEphemeral().

Test: atest com.android.car.user.CarUserServiceTest \
      android.car.apitest.CarDevicePolicyManagerTest#testRemoveUser_whenDisallowed
Bug: 170887769

Change-Id: If797ace64c0fa0262116f649212bbcb1d61e2046
1 file changed