Fix interruption + overscroll bug

This CL fixes a tricky interruption + overscroll bug: because the scene
in which an element is placed can change when overscrolling, the
computation of the interruption deltas for placement-related values
should also be saved on the scene we are not placing the element in if
the element is shared in both scenes. This avoids jumpcuts that can
happen when an interruption is ongoing and that we start overscrolling,
placing the element in another scene.

Bug: 290930950
Test: atest ElementTest
Flag: com.android.systemui.scene_container
Change-Id: Id9ba18e70013ca4561ad8e35e25be5d8d69d6789