Fix navigation input consumer not working when first window is invisible

The nav InputConsumer should be the top window without being related
to some window or it may be hidden if the window is not visible.

Test: atest com.android.server.wm
Test: atest WindowInsetsControllerTests
Bug: 167940326
Merged-In: I842114e68eaedaa008972a0a84c6b6394174f232
Change-Id: I842114e68eaedaa008972a0a84c6b6394174f232
(cherry picked from commit 74a9a609)