Handle trampoline activites in different tasks

When the app uses a trampoline activity that launches in a different
task than the main task, we fail to show recents when the task is
docked and the user launches the trampoline activity from home. Add
logic to handle this case.

Bug: 28368989
Change-Id: Iea29e6cd1a9919da0e856955691fac4792e30604