Inject LockPatternUtils into KeyguardUpdateMonitor

For better testability of KeyguardUpdateMonitor. We don't actually want
to register callbacks to the real lock settings. But if we ever do in
tests, we make sure to cleanup the callbacks in
KeyguardUpdateMonitor.destroy().

Test: atest SystemUITests
Fixes: 156230507
Change-Id: I2548c15da29ef5a15f6d3b512fbfd344ca2bd355