### Godot version

Godot Engine v4.0.stable.official.92bee43ad

### System information

Windows 10

### Issue description

The documentation states that passing ```null``` into the image parameter of ```set_custom_mouse_cursor``` will change it back to the system cursor, however I find that it removes the cursor's image entirely, rather than setting it to the system's cursor.


### Steps to reproduce

```var isimage = false
var theimage = load("res://final.png")

func _on_my_button_pressed():
    if isimage == false:
        Input.set_custom_mouse_cursor(theimage, Input.CURSOR_ARROW, Vector2(16,16))
        isimage = true
        
    else:
        Input.set_custom_mouse_cursor(null)
        isimage = false```

When the button is pressed, the cursor is meant to change to the new cursor. When it has been pressed a second time, it changes back to the default cursor. However, upon pressing it a second time, it simply disappears. The cursor becomes visible again when the cursor exits and re-enters the window.

### Minimal reproduction project

[null mouse.zip](https://github.com/godotengine/godot/files/10901969/null.mouse.zip)

_THREAD_SAFE_METHOD_
#if defined(VULKAN_ENABLED)
	if (context_vulkan) {
		context_vulkan->set_vsync_mode(p_window, p_vsync_mode);
	}
#endif
#if defined(GLES3_ENABLED)
	if (gl_manager) {
		gl_manager->set_use_vsync(p_window, p_vsync_mode != DisplayServer::VSYNC_DISABLED);
	}
#endif
}
DisplayServer::VSyncMode DisplayServerWindows::window_get_vsync_mode(WindowID p_window) const {
	_THREAD_SAFE_METHOD_
#if defined(VULKAN_ENABLED)
	if (context_vulkan) {
		return context_vulkan->get_vsync_mode(p_window);
	}
#endif
#if defined(GLES3_ENABLED)
	if (gl_manager) {
		return gl_manager->is_using_vsync(p_window) ? DisplayServer::VSYNC_ENABLED : DisplayServer::VSYNC_DISABLED;
	}
#endif
	return DisplayServer::VSYNC_ENABLED;
}
void DisplayServerWindows::set_context(Context p_context) {