Lets use the same resId as floating bubbles, works better with tests

The tests look up this id to check if bubbles are expanded, if these
are the same in floating / bar mode then some of the tests can be
reused for both.

Flag: com.android.wm.shell.enable_bubble_bar
Test: atest BubbleBarTest (with other CL)
Bug: 347312208
Change-Id: I544b78a1ca1366f51ea2b0507da8a68f9fe2e51e