[flexiglass] Switch ShadeHeader expanded format to depend on layoutState

Moved ShadeHeader's expanded format to be derived from layoutState instead of using an animatedSceneFloat to avoid issues stemming from the animated value being incorrect at the very beginning of a transition (previous solution was meant to be a stopgap)

Bug: 333132303
Test: checked both dual sim icons and battery view change correctly according to QS expansion
Test: checked ShadeHeader does not recompose unnecessarily during Shade<->QS transition
Flag: ACONFIG com.android.systemui.scene_container DEVELOPMENT
Change-Id: I86af32e0a43c7f8d6b061c97d2d7c2642cebda69