Invalid isMount behavior in React.StrictMode

[undermuz]

https://react.dev/reference/react/StrictMode

Using React StrictMode causes effects to re-run an extra time to find bugs caused by missing effect cleanup. This causes the following code to not work as expected: https://github.com/atlassian/pragmatic-drag-and-drop/blob/main/packages/react-beautiful-dnd-migration/src/draggable/index.tsx#L250

const isMountedRef = useRef(true);
	useEffect(() => {
		return () => {
			isMountedRef.current = false;
		};
	}, []);

This code throws an error in development mode: https://github.com/atlassian/pragmatic-drag-and-drop/blob/main/packages/react-beautiful-dnd-migration/src/draggable/index.tsx#L422

rbdInvariant(isMountedRef.current, 'isMounted onBeforeDragEnd');