Close overlay onTaskStackChanged when All Apps is visible.

We have too many cases where All Apps can relaunch the current task
behind it to the point where it will not be sustainable to manually
close AFVs in all of these cases.

Test: Manual
Fix: 299169192
Fix: 299169075
Fix: 299169073
Flag: No
Change-Id: If3d9aa756ff5e5d6fbaf5f91d2ccc0c5c11a5c23