Return START_TASK_TO_FRONT when launching transient hide task

Otherwise DELIVER_TO_TOP may abort the transition.

This mainly happens when a swipe-to-home animation is not
finished yet, launch the swiped app again from home. If the
transition is aborted, the surface could keep invisible.

Bug: 280387453
Test: Swipe from split to home and launch the app immediately
      by clicking the app icon on launcher to launch the app
      again.
Change-Id: I72e576969473e3430eea02c98b62b71dc1d9e26e