### 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)

}
		}
	} else if (IsClipboardFormatAvailable(CF_TEXT)) {
		HGLOBAL mem = GetClipboardData(CF_UNICODETEXT);
		if (mem != nullptr) {
			LPTSTR ptr = (LPTSTR)GlobalLock(mem);
			if (ptr != nullptr) {
				ret.parse_utf8((const char *)ptr);
				GlobalUnlock(mem);
			}
		}
	}
	CloseClipboard();
	return ret;
}
typedef struct {
	int count;
	int screen;
	HMONITOR monitor;
} EnumScreenData;
static BOOL CALLBACK _MonitorEnumProcPrim(HMONITOR hMonitor, HDC hdcMonitor, LPRECT lprcMonitor, LPARAM dwData) {
	EnumScreenData *data = (EnumScreenData *)dwData;
	if ((lprcMonitor->left == 0) && (lprcMonitor->top == 0)) {
		data->screen = data->count;
		return FALSE;
	}
	data->count++;
	return TRUE;
}
static BOOL CALLBACK _MonitorEnumProcScreen(HMONITOR hMonitor, HDC hdcMonitor, LPRECT lprcMonitor, LPARAM dwData) {