Change window highlight style in WindowHeapDelegate
Currently FrameSvgItem is used to highlight selected or hovered windows. But the problem with it is that it's a bit heavyweight. As a way around it, we could put it in a Loader, but that's going to be bring a set of other challenges.
As an alternative solution, this change replaces FrameSvgItem with a simple outline. It still produces decent visuals and it's simpler.
Edited by Vlad Zahorodnii