Exclude transient activity from hide-tasks

If the recents activity does not exist, it will go the standard
activity launch process, which will move the task of transient
activity to top before calling setTransientLaunch. That causes
it to be added into the hide-tasks and uses HIDE transition.

Bug: 273770222
Test: atest NexusLauncherTests:com.android.quickstep. \
      FallbackRecentsTest#testOverview

Change-Id: I725a8d62377593d47e11e3ac0d6785ace0269b25