gloverlay: Recompute geometry when caps change

Set geometry_changed when setting caps so that the geometry is
recomputed correctly with the new dimensions.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/9434>

subprojects/gst-plugins-base/ext/gl/gstgloverlay.c

@@ -397,6 +397,7 @@ gst_gl_overlay_set_caps (GstGLFilter * filter, GstCaps * incaps,
 
   overlay->window_width = width;
   overlay->window_height = height;
+  overlay->geometry_change = TRUE;
 
   return TRUE;
 }