[Flexiglass] Update the new HeadsUpAnimator from the HUN placeholder

Follow the refactor of NotificationsHunSharedAnimationValues, and wire
in the new HeadsUpAnimator class with SceneContainer enabled.

Fixes: 400416268
Flag: com.android.systemui.notifications_hun_shared_animation_values
Test: SceneContainerFlag ON, NotificationsHunSharedAnimationValues OFF -> run HUN intro/outro

Change-Id: Iee64480bb5a2615a35370b67475d2ba368fb9d2b