Delete dependent TaskFragments in the same transaction

When finishing the last activity in a container that has dependent
containers, make sure to delete those in addition to just finishing
activities. This will ensure that containers with activities from
different apps will be properly cleaned up.

Bug: 195108809
Test: Launch a container to side with 'finishSecondaryWithPrimary'
configuration, finish the primary container with swipe from side.
Test: Do the above for activities in different apps.

Change-Id: I746055fd02894d8221cace10d556992e2dba31b5