Show hotseat instead of stashed taskbar handle after entering stage split from...

Show hotseat instead of stashed taskbar handle after entering stage split from fullscreen app via keyboard shortcut

Besides finishing the recents animation from fullscreen app, we also need to update the taskbar state

Fixes: 323561157
Test: Go to a fullscreen app, trigger the split shortcut, make sure the hotseat icons are visible on the home screen
Change-Id: I36f47846ed0bc7f7036ae22452a28efc9cb09bc7