Simplify edit tile list state

The list state now only tracks the current tiles because the available tiles are hidden during a drag movement. This simplifies the logic in EditTileListState and helps with unnecessary recompositions

Bug: 346991759
Flag: com.android.systemui.qs_ui_refactor
Test: EditTileListStateTest
Test: DragAndDropStateTest
Change-Id: Id51bc657038201e4edb89e10d9a3e70246574bb6