Update placement of the nav bar in persistent taskbar for 3 button nav

Implemented nav bar placement update to be located opposite to the
bubble bar.
When bubble bar is moved to the other side of the bar, 3 button nav will
swap sides (without animation).
If taskbar has to be repositioned it does that with the animation.

Test: TaskbarViewControllerTest
Bug: 346381754
Flag: com.android.wm.shell.enable_bubble_bar
Change-Id: Id031706183c60cbd9c67537b01530acb43bae614