Transfer PipContentOverlay when swipe to home with Shell transition

Update launcher to pass the taskId to Shell, so that Shell can reparent
the overlay from the remote transition leash to the Task leash.
Otherwise the overlay will be removed with the transition leash when
transition is finished.

Bug: 222030101
Test: verify with swipe to home with Shell transition
Change-Id: I838c22951fdf79c3213f2c9b1cb73a4a90341597