Fix user bio bug.

ui/src/components/user.tsx

@@ -384,12 +384,14 @@ export class User extends Component<any, UserState> {
                 )}
               </ul>
             </h5>
+            {user.bio && (
               <div className="d-flex align-items-center mb-2">
                 <div
                   className="md-div"
                   dangerouslySetInnerHTML={mdToHtml(user.bio)}
                 />
               </div>
+            )}
             <div className="d-flex align-items-center mb-2">
               <svg class="icon">
                 <use xlinkHref="#icon-cake"></use>