Switch to screenshot when finishing recents animation for split select

* There's a situation where we can also let the live-tile play
if it wasn't the one selected for split select, but there's
some bug w/ the focused task that causes the thumbnail and live tile
translations to be incorrect.
* But this maintains parity.

Fixes: 255915066
Test: Starting/ending/ignoring live tile in split
never shows the cutout

Change-Id: I2f63ca44a5a1cc16df12e7b3b06ca211dc995f8d