Move things from ContainerViewModel to OverlayViewModel

QuickSettingsContainerViewModel should only contain things that are
shared among different scenes that use QuickSettings (including
QSFragmentCompose). Elements and values that are exclusive to
QuickSettingsShadeOverlay should go in the respective view model.

Also QuickSettingsContainer makes no assumption about scene container.

Test: atest com.android.systemui.qs.ui.viewmodel
Test: manual, dual shade
Flag: com.android.systemui.scene_container
Bug: 420960164
Change-Id: I92dab12d53fc270fc77ab15f6730146a28e4c651