Adjust drag regions to accomodate split-minimized home

Basically, this doesn't constrain home's drag bounds to
its stack if it is on top of its parent since sysui has
adjusted the surface crop for these cases.

On the other side, anything in the primary stack must
subtract the home's bounds from its own if home is the
top secondary task.

Bug: 154832406
Test: With a minimized dock, open quick-search and drag
      an app icon onto the launcher.
Change-Id: Id25ec11de85530b2f43ecc0dda6864077a271ba5