Ensure alpha is reset on QS expansion

Setting a value of 1f when QS is fully expanded
allows for HUNs to show when unlocked.

Fixes: 329231698
Test: atest SharedNotificationContainerViewModelTest
Flag: ACONFIG com.android.systemui.migrate_clocks_to_blueprint
TEAMFOOD

Change-Id: I3a833d61ecba3d3b36ea0f6e581f7bf4fd98b0e3