Pass back entire split tree for remote animations

* If there's a remote animation we pass back the entire top
level split root along w/ the stage roots in the TransitionInfo
object.
* We also ensure all the changes correctly have the parent token
set on them (execpt for the top most split root)
* Normally all the roots don't get added from core because
sometimes they actually aren't changed, ex: if an app pair is open
and then a different app pair is tapped, the roots aren't changing,
only the leaf tasks under them are.
However, for animation purposes we don't want to keep forking logic
on the launcher side for these different cases, so client assumes
the entire tree is there and ready to animate.

Bug: 399037701
Test: Open app pairs from desktop windowing + normal taskbar
Flag: EXEMPT bugfix

Change-Id: I1cabfc3593b3da8c99a10ae63f5c9ecbc4788f88