Always collapse expanded view when dragging a bubble from bubble bar

Previously we only collapsed the expanded view when the expanded bubble
was being dragged. This caused issues with the bubble bar reposition
logic. The expanded view got detached from the the bubble bar when the
bar moved to the other side.
Update the drag logic to always collapse the expanded view when any
bubble is dragged. When drag stops, expand the previously expanded
bubble again.

Bug: 330585402
Flag: ACONFIG com.android.wm.shell.enable_bubble_bar DEVELOPMENT
Test: atest BubblesTest
Test: check that expanded bubble collapses during drag
  - have 2 bubbles in the bubble bar (A, B)
  - select and expand bubble A
  - start dragging bubble B
  - bubble A should collapse
  - release bubble B
  - bubble A should expand again
Test: check that selected bubble expands after a bubble is dismissed
  - have 2 bubbles in the bubble bar (A, B)
  - select and expand bubble A
  - dismiss bubble B by dragging it to dismiss target
  - bubble A should expand

Change-Id: I5fc47461c1e857073c260c146f924fb444b39e45