…View is already off screen

Speculative fix based on the Firebase logs which shows that on a second check
of R.id.tab_wrapper it is not found the screen.
It may be because after `advanceToHalfExpandedState` and before getting a
reference to it in `waitForTabTrayBehaviorToIdle` it was already animated off
the screen.
With this in mind I've added a null check for the view reference before trying
to register an idling resource on it's Behavior.

Also added and used a way to click at a specific location in a View, not just
in the default middle in the View.
It was observed from the Firebase videos that a "click" on the topBar actually
selected the private tabs section. This would leave us to believe that the
"click" was caught by that other View which was placed above the x,y middle of
the topBar.