Add support for fromSource in nested scroll

STL's nested scroll connection now uses the information available in the
 DraggableHandler to compute the current action (Swipe.Resolved).

Test: atest DraggableHandlerTest
Bug: 366387626
Flag: com.android.systemui.scene_container
Change-Id: Ib6b53679de0a3a1aa8bf4fe096f3bb04f3292c8f
3 files changed