Refactored shelf transformation code to support animations

The shelf positions are now applied in each frame if there
is an animation in order to not have weird transitions
when a notifications moves in / out of the shelf.

Test: Add notifications, swipe one away see animation out of the shelf
Bug: 32437839
Change-Id: Ie50362c85ec2fb2a9822de6a387167913d7a58dd
5 files changed