Provide displayName to withSnackbar HOC

[Lukas-Kullmann]

The current implementation of the withSnackbar HOC does not provide a displayName. For testing purposes (e.g. Snapshot tests), it would be great if it would provide one.

Example implementation:

const withSnackbar = Component => {
    const WrappedComponent = props => (
        <SnackbarContext.Consumer>
            {handlePresentSnackbar => (
                <SnackbarContextNext.Consumer>
                    {context => (
                        <Component
                            {...props}
                            onPresentSnackbar={handlePresentSnackbar}
                            enqueueSnackbar={context.handleEnqueueSnackbar}
                            closeSnackbar={context.handleCloseSnackbar}
                        />
                    )}
                </SnackbarContextNext.Consumer>
            )}
        </SnackbarContext.Consumer>
    }

    WrappedComponent.displayName = `withSnackbar(${Component.displayName || Component.name || 'Component'})`;

    return WrappedComponent;
);