Remove UserController.sethasTopUi because it doesn't have any effect.

These lines were added in ag/25202314 but they don't have any effect
due to ag/14508386.

Bug: 308106771
Flag: ACONFIG android.multiuser.allow_using_all_cpu_cores_during_a_user_switch DEVELOPMENT
Test: NA
Change-Id: Ie27a09f3b7a7c30bfe04e8188143ceac441c4ba7