Avoid UserManager#isUserLocked

Fixes: 140053632
Test: atest KeyguardUpdateMonitorTest
Test: atest KeyguardIndicationControllerTest
Test: reboot, look at KeyguardIndication (has message)
Test: add new user, look at KeyguardIndication (no message)
Test: change to secondary user, look at KeyguardIndication (has message)
Test: change to secondary user that doesn't have a pwd, look at KeyguardIndication (no message)
Change-Id: Ica9c5fd44b5a010294981031674f42cd841c7d52