Add support for interruptions in shared values

This CL adds support for interruptions when animating shared
element/scene values, in a very similar way to what was already done for
the size, offset and alpha of elements in ag/26597678.

See b/290930950#comment29 for before/after videos.

Bug: 290930950
Test: atest ElementTest
Flag: com.android.systemui.scene_container
Change-Id: Ie2944544438aa75cc7d8bf4683ed4646d9103ef3