Update voice interaction animation

Add new tween type SLOW_OUT_LINEAR_IN and use it for the end
animation.

BUG=b:35624617
TEST=build and flash locally, saw the animation changes

Review-Url: https://codereview.chromium.org/2947843005
Cr-Commit-Position: refs/heads/master@{#481608}
3 files changed