Reports top resumed activity state loss when no focused task

There was no other focusable task while the top resumed activity
finished. So, the system didn’t report top-resumed-loss at that
moment, but was reported to the client after home activity started
and resumed afterward. That resulted in an app crash since the
activity client record was already destroyed.

Bug: 284552716
Test: verified locally by keeping one focused app task and
      force stopped all others tasks
Change-Id: Ibe6d38e1c4db328b8bfc7bae70fd14ba6f131a25