Fix issue with recent task being replaced by task with another windowing mode

- ag/3762067 is not sufficient to fix the regression from stack id to
  activity type and windowing mode.  When finding a task in the recents
  list to remove and replace with a new task, we need to treat tasks with
  different windowing modes as separate tasks.

Bug: 78291664
Test: Launch play movies, enter PIP and ensure that the main activity task
      still shows in overview

Change-Id: Id1fddfe580bd6bfab8e618930cec82e1e4363ce0