Updated toolbar and dialpad interactions in NUI.

Toolbar, Dialpad, Bottom Nav, FAB and Search now all show
and hide properly according to the state of the application.

Follow up CLs will include:
 - saving/restoring state
 - sending query to search fragment to display results

Bug: 181512198
Test: MainActivityIntegrationTest
PiperOrigin-RevId: 182259200
Change-Id: I1309d8df2a5425bf051e52a459a1f78e1157fe08