message: Fix empty lightbox when there is no avatarUrl
diff: @@ -137,6 +137,11 @@ module.exports = React.createClass({
  const avatarUrl = this.props.room.getAvatarUrl(
  MatrixClientPeg.get().getHomeserverUrl(),
  null, null, null, false);
  +
  + if (!avatarUrl) {
  + return;
  + }
  +
  const ImageView = sdk.getComponent("elements.ImageView");
  const params = {
  src: avatarUrl,
  