Fix bug where shade is infinitely squishy after wallpaper change

This change fixes a bug where
opening an empty shade after wallpaper update
=> messes up qs button unfurling
=> hides the "no notifications" text

This bug happened because
=> wallpaper change causes theme change
=> on theme change, NSSLC reinflates EmptyShadeView
   with visibility=false
=> nothing resets EmptyShadeView visiblity=true on shade open
=> AmbientState has 0 visibleChildren during shade open,
   so stackHeight is 0 and expansionFraction is infinity

The solution is to have NSSLC
update EmptyShadeView visibility after re-inflation.

Fixes: 215038354
Fixes: 218501868
Fixes: 218380326
Test: have no notifications, change wallpaper, open shade
     => qs button squishiness animates fine
     => "no notifications" text shows up fine
     => log squishiness: no infinity or NaN

Change-Id: Iaa10605079db7edc79771a1cd9f4cc17f847c4cb
(cherry picked from commit d2adae5b)