Avoid using AbstractClient::adjustedSize()
X11Client tolerates passing shaded geometry to moveResize() and in many cases kwin already does that.
Another issue is that this doesn't align well with new async geometry handling abstractions. pos() can't be used because it corresponds to the current frame position.
We can safely pass the last move resize geometry. It simplifies code a bit and makes sure that everything works as expected with the move resize geometry.
Abstract clients tolerate passing the shaded window geometry to moveResize().
But the main issue with applyWindowRules() is that it uses the current frame geometry even though it calls moveResize(). It's not a big deal but it's error prone.
This change ports applyWindowRules() to the move resize geometry, which makes code more straightforward and ensures that kwin uses right geometry type with moveResize().