### 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)

switch (p_feature) {
		case FEATURE_SUBWINDOWS:
		case FEATURE_TOUCHSCREEN:
		case FEATURE_MOUSE:
		case FEATURE_MOUSE_WARP:
		case FEATURE_CLIPBOARD:
		case FEATURE_CURSOR_SHAPE:
		case FEATURE_CUSTOM_CURSOR_SHAPE:
		case FEATURE_IME:
		case FEATURE_WINDOW_TRANSPARENCY:
		case FEATURE_HIDPI:
		case FEATURE_ICON:
		case FEATURE_NATIVE_ICON:
		case FEATURE_SWAP_BUFFERS:
		case FEATURE_KEEP_SCREEN_ON:
		case FEATURE_TEXT_TO_SPEECH:
		case FEATURE_SCREEN_CAPTURE:
			return true;
		default:
			return false;
	}
}
String DisplayServerWindows::get_name() const {