Remove the dependency of SwipeAnimation on STLImpl

This CL removes the dependency that SwipeAnimation has on
SceneTransitionLayoutImpl. This will allow users of STL to easily create
their own SwipeAnimation to drive an STLState.

Bug: 362727477
Test: atest DraggableHandlerTest
Flag: com.android.systemui.scene_container
Change-Id: I2f7486442dc257674a7b7781b35938c7b1fd4bf0