Recalculate max notifs on media change

Specifically when remote media comes on, max notifications
was not getting recalculated. This follow the legacy logic
of listening to the view onLayoutChange event.

Fixes: 325066639
Test: manual - cast remote media and observe changes on
keyguard
Flag: ACONFIG com.android.systemui.migrate_clocks_to_blueprint
DEVELOPMENT

Change-Id: I8d5f306a0461e625035b32476c9c60c37f7601ef