Correct layout/draw/animation interleaving for insets callbacks

See WindowInsetsAnimationCallback.onPrepare for detailed
description of new behavior.

Also rename InsetsSourceConsumer.setVisible to setRequestedVisible
to communicate that this is client intent vs. current state.

Test: windowinsetstest application
Bug: 111084606
Change-Id: Id35c60e0f59a8aa4f0d300220391d1e2b96a91fd