Include bubble bar location in taskbar announcement

When bubble bar has bubbles, it will be expanded together with taskbar.
Include information about bubble bar appearing together with the taskbar
announcement. During expand include the location of the bubble bar,
whether it is on the left or right.

Bug: 344675357
Flag: com.android.wm.shell.enable_bubble_bar
Test: manual, enable talkback and check that taskbar expand announcement
  includes information about bubble bar, check that when bar is on left,
  announcement includes left and bar is right, announcement says right
Change-Id: I116ed531fe7032940478451508b37f4fd0bc98ff