Clean up AmbientStatusBarViewController's Status Bar Listener.

This changelist moves registration of AmbientStatusBarViewController's
StatusBarWindowStateListener from construction to initialization and
then adds unregistering to destroy.

Test: atest AmbientStatusBarViewControllerTest#testStatusBarWindowStateControllerListenerLifecycle
Bug: 360088321
Flag: EXEMPT bugfix
Change-Id: I67f7ba02620649ebdcce958bd37f3c39117eb46b