Add extra logging for SysUI's userUnlocked cache

Check dumpsys of SysUI for:
 - KeyguardUpdateMonitorLog for logs with:
 userUnlocked/userStopped/userRemoved/userUnlockedInitialState
 - KeyguardUpdateMonitor userUnlockedCache and actualUserUnlocked
 - [not in this CL] KeyguardIndication updateLockScreenUserLockedMsg
   logs

Flag: EXEMPT bugfix
Test: see SysUI dumpsys for logs
(adb shell dumpsys activity service com.android.systemui)
Bug: 333656491

Change-Id: I607124157d15f64396c4c5a729d76e80104456b8