XRLayer stereo layout not supported in the fallback  #413

  const video = useMemo(() => {
    const result = document.createElement('video');
    result.src = 'https://threejs.org/examples/textures/MaryOculus.webm';
    result.crossOrigin = 'anonymous';
    return result;
  }, []);
  return   
              <XRLayer
                position={[0, 0, -0.5]}
                onClick={() => video.play()}
                scale={0.5}
                src={video}
                // shape={'cylinder'}
                layout={"stereo-left-right"}
              />