d3d11videosink: Fix for force-aspect-ratio setting when rendering on shared texture

Set specified force-aspect-ratio value on window object
in case of shared texture rendering as well

Fixes: gstreamer/gstreamer#1304
Part-of: <gstreamer/gstreamer!2671>
23 jobs for !2671 with d3d11videosink-far-dummywindow in 37 minutes and 7 seconds (queued for 1 second)
merge request