dillon1000/react

Allow global mutation within useEffect (#2646)

Summary: Currently Forget bails on mutations to globals within any callback function. However, callbacks passed to useEffect should not bail and are not subject to the rules of react in the same way.

We allow this by instead of immediately raising errors when we see illegal writes, storing the error as part of the function. When the function is called, or passed to a position that could call it during rendering, we bail as before; but if it's passed to `useEffect`, we don't raise the errors.