Add epic hack so vsync can be toggled in run-time from script. Fixes #14458.

Call needs to be routed via visual server to reach the proper thread.

servers/visual_server.h

@@ -980,6 +980,8 @@ public:
 
 	virtual void set_debug_generate_wireframes(bool p_generate) = 0;
 
+	virtual void call_set_use_vsync(bool p_enable) = 0;
+
 	VisualServer();
 	virtual ~VisualServer();
 };