Fix clocks moving to the left on connected display after locking

The onTargetRegionChanged callback was causing clocks to shift on the left side of the screen after locking the device twice.

The Presentation already adds the clock with center gravity, and it doesn't seem to be needed to pass these events over.

The Weather clock still looks wrong (not centered correctly), but this CL doesn't seem to change its behaviour.

Bug: 362719719
Bug: 353886316
Test: KeyguardDisplayManagerTest + show keyguard on external display + turn screen off/on a few times, observe the clock stays centered
Flag: com.android.systemui.shade_window_goes_around
Change-Id: I501ec143232ccdba7a70e7c9f1a08fc0f1daae46