d3d11screencapture: Fix missing/outdated cursor shape

d3d11screencapture: Fix missing/outdated cursor shape

d3d11screencapture can miss a cursor shape to draw or draw an outdated cursor shape.
 - AcquireNextFrame only provides cursor shape when there is one update
 - current d3d11screencapture skips cursor shape when mouse is not drawn

So, if a gstreamer application uses d3d11screencapture with cursor initially not drawn
"show-cursor"=false and then switches this property to true, the cursor will not be
actually drawn until AcquireNextFrame provides a new cursor shape.
This commit makes d3d11screencapture always update the cursor shape information, even
if the mouse is not drawn. d3d11screencapture will always have the latest cursor shape
when requested to draw it.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2485>