### 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)

iconinfo.yHotspot = p_hotspot.y;
			iconinfo.hbmMask = mask;
			iconinfo.hbmColor = bitmap;
			cursors[p_shape] = CreateIconIndirect(&iconinfo);
		}
		Vector<Variant> params;
		params.push_back(p_cursor);
		params.push_back(p_hotspot);
		cursors_cache.insert(p_shape, params);
		if (p_shape == cursor_shape) {
			if (mouse_mode == MOUSE_MODE_VISIBLE || mouse_mode == MOUSE_MODE_CONFINED) {
				SetCursor(cursors[p_shape]);
			}
		}
		DeleteObject(mask);
		DeleteObject(bitmap);
		ReleaseDC(nullptr, dc);
	} else {
		
		if (cursors[p_shape]) {
			DestroyIcon(cursors[p_shape]);
		}
		cursors[p_shape] = nullptr;
		CursorShape c = cursor_shape;
		cursor_shape = CURSOR_MAX;
		cursor_set_shape(c);
		cursors_cache.erase(p_shape);
	}
}
bool DisplayServerWindows::get_swap_cancel_ok() {