Handle suppressed bubbles

Hide or show bubble based on suppression signals from shell.
If this is the only bubble, hides or shows the bubble bar.

Bug: 273316505
Test: have a single bubble in the bubble bar, suppress the bubble,
  observe that bubble is hidden and bubble bar is not shown,
  unsuppress the bubble, check that bubble bar and bubble is shown
  again, perform check with transient and persistent taskbar
Test: have multiple bubbles, suppress one bubble, check that this bubble
  is not shown, but the bubble bar remains visible with other bubbles,
  perform the check with transient and persistent taskbar
Test: have a single bubble in bubble bar that is suppressed, receive
  notifications to trigger new bubbles, observe bubble bar is shown for
  new bubbles, check that after unsuppressing bubble, it is added back,
  perform the checks with tranient and persistent taskbar
Test: suppress a bubble and rotate the device to trigger launcher
  recreation, check that after unsuppress, the bubble is added back

Flag: com.android.wm.shell.enable_bubble_bar

Change-Id: I17e5cec750a2666feecc62213a3e8fc204ee510a