Use the broadCast Receiver to detect when the user is switched and register...

Use the broadCast Receiver to detect when the user is switched and register the notificationListner when the user is switched.

By default the SysUI is booted as User0 after which it switches to the current logged in user. We have to listen to the broadcast receiver to know when that happens.

Bug: 123432748
Test: Manual
Change-Id: I567ae0c53df277097de53475f9144d739fa4a18d
(cherry picked from commit e81756e4d417150ada4eb817f475ad4916751e27)