TextureViewer: fix wheel zooming on HiDPI screens
TextureViewer: fix wheel zooming on HiDPI screens

Without adjusting for pixel ratio it zoomed in into a wrong place.

baldurk/renderdoc,baldurk/renderdoc,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,Zorro666/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,Zorro666/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc