Access to loading errors

[mdouglass]

Hello,
I'm building out our website to support our first unity webgl version of our games and react-unity-webgl has been working great. One thing I've noticed is that if we misconfigure the loaderUrl then we don't get any notice of it and the page just seems to hang. It would be nice to be able to display a fallback error message in that case (certainly would help during dev).

I checked initialisationError and that is empty in this case. Looking internally, I believe what I want access to is UnityLoaderStatus from the useUnityLoader hook. Would you be willing to expose that or is there another way to get access to that?

Would be happy to provide a PR that exposes it if that's acceptable.

Thanks!