Modify pin widget dialog open-close animation.

Pin widget sheet should open from bottom up and close on drag down.
Behaviour with navigation bar is similar to that of widgets bottom sheet.

Add a drag layer and reuse AbstractSlideInView for open-close
animation.

Test: Tested manually- opening, closing through dragging/ cancel button/
back button. Adding widget to screen by dragging/ add to home screen
button.
Bug: 186124244

Change-Id: I4b77d5bdd4ed1689b651847dfed69d19cafa7456