Handle configuration changes in home controls complication.

This ensures the home controls chip on the dream correctly updates when
the dark/light theme changes.

Test: adb shell cmd uimode night {no|yes} while dreaming
Test: atest DreamHomeControlsComplicationTest
Flag: NA
Fixes: 309137742

Change-Id: I3153d13599ff2e09636486fdb64cdb9caf5ced10