Added override for window_get_vsync_mode in display_server_web.cpp

(cherry picked from commit a932c5e81d5965063d3eb2a364c8b1567b820f88)

platform/web/display_server_web.cpp

@@ -1070,6 +1070,10 @@ bool DisplayServerWeb::can_any_window_draw() const {
 	return true;
 }
 
+DisplayServer::VSyncMode DisplayServerWeb::window_get_vsync_mode(WindowID p_vsync_mode) const {
+	return DisplayServer::VSYNC_ENABLED;
+}
+
 void DisplayServerWeb::process_events() {
 	Input::get_singleton()->flush_buffered_events();
 	if (godot_js_input_gamepad_sample() == OK) {

platform/web/display_server_web.h

@@ -213,6 +213,8 @@ public:
 
 	virtual bool can_any_window_draw() const override;
 
+	virtual DisplayServer::VSyncMode window_get_vsync_mode(WindowID p_vsync_mode) const override;
+
 	// events
 	virtual void process_events() override;