Swipe down should hide ActionList

Added an AnchoredDraggableState to control swiping vertically and
dismissing the list.
The animation is driven by springs to provide a smooth experience.

Fixes: 418032681
Test: manually swipe down
Test: tap outside to close
Flag: com.android.systemui.enable_underlay
Change-Id: I8136d4f2a9499fe50235e8ec8ea3fae277255809