Update bubble bar bounds in shell

Shell keeps track of bubble bar bounds for positioning and animating the
expanded view.
Bubble bar location can be changed when dragging the expanded view or
bubble bar itself.
Previously bounds were only reported when expanding a bubble. But after
adding drag support, bounds can change outside of expand action.
Implement a new bubbles API to report bubble bar bounds to shell
whenever they change in launcher.
Keep track of last reported bounds to ensure that we only send bounds
over when they change and when expand API has not already reported the
bounds.

Bug: 332423960
Flag: ACONFIG com.android.wm.shell.enable_bubble_bar DEVELOPMENT
Test: drag expanded bubble from one side to the other, collapse it,
  observe that collapse animation collapses the view into the bar
Change-Id: If1bf31a04b8f134a1b055fddccd276e924ed98b6