Fix CSGShape not updating on changing visibility

Hiding CSGShape should force the CSG operation to skip it which is intented
behaviour according to how CSGBrush is created for each shape.

modules/csg/csg_shape.cpp

@@ -531,6 +531,13 @@ void CSGShape::_notification(int p_what) {
 		}
 	}
 
+	if (p_what == NOTIFICATION_VISIBILITY_CHANGED) {
+
+		if (parent) {
+			parent->_make_dirty();
+		}
+	}
+
 	if (p_what == NOTIFICATION_EXIT_TREE) {
 
 		if (parent)