Fix crash on user switch.

Recent changes in SystemUI expects taht the navigation bar have a parent
view that is not the WindowManager. Inflate navigation_bar_window as the
parent view for the CarNavigationBar as this is the view that the
default StatusBar users.

Test: verified that user switching no longer results in a crash
Bug: 36070562
Change-Id: I3e9c2efd4caa7b36478e621bc2dd6f7e41ad7fbd