Changes signature of `onMessage`

[andreialecu]

See:

webshell/packages/webshell/src/hooks/useWebshell.ts

Line 93 in 60af580

typeof onMessage === 'function' && onMessage(nativeEvent);

I believe this should be onMessage({ nativeEvent });

With the current behavior, what seems to happen is that e.nativeEvent.data does not exist - and that's how it's supposed to work, but e.data does.