Animations for new bubble while stack is collapsed

Bug: 170302562
Test: have no bubs, add bub => bub moves up to finalY
Test: have bubs, add bub => new bub moves up, old bubs move down
Test: update existing bub => updated bub swoops above stack, then
      moves down to finalY with other bubs
Test: the above on portrait left/right && landscape left/right

Change-Id: I1f9e38fed9ad66ad243700082981f75418c64bf5