minor fixes around remote avatars

src/widgets/avatar-upload.jsx

@@ -34,7 +34,7 @@ export default class AvatarUpload extends React.Component {
   render() {
     // Randomize id value in case more than one AvatarUpload is shown
     // at the same time.
-    const randId = 'file-input-avatar-' + (Math.random() + '').substr(2);
+    const randId = 'file-input-avatar-' + ('' + Math.random()).substring(0, 4);
     const className = 'avatar-upload' + (this.props.readOnly ? ' read-only' : '');
     return (
       <div className={className}>

src/widgets/topic-desc-edit.jsx

@@ -10,8 +10,8 @@ import AvatarUpload from './avatar-upload.jsx';
 import InPlaceEdit from './in-place-edit.jsx';
 import TagManager from './tag-manager.jsx';
 
-import { AVATAR_SIZE, MAX_AVATAR_BYTES, MAX_EXTERN_ATTACHMENT_SIZE,
-  MAX_INBAND_ATTACHMENT_SIZE, MAX_TITLE_LENGTH, MAX_TOPIC_DESCRIPTION_LENGTH } from '../config.js';
+import { AVATAR_SIZE, MAX_AVATAR_BYTES, MAX_EXTERN_ATTACHMENT_SIZE, MAX_TITLE_LENGTH,
+  MAX_TOPIC_DESCRIPTION_LENGTH } from '../config.js';
 import { imageScaled, blobToBase64, makeImageUrl } from '../lib/blob-helpers.js';
 import { arrayEqual, theCard } from '../lib/utils.js';