Code review suggestions.

* Reply to broken images.
* Remove 'viewportWidth' from SendMessage.

src/widgets/doc-preview.jsx

@@ -46,7 +46,6 @@ export default class DocPreview extends React.PureComponent {
         <SendMessage
           noInput={true}
           tinode={this.props.tinode}
-          viewportWidth={this.props.viewportWidth}  // Used by `formatter`.
           replyTo={this.props.replyTo}
           formatter={this.props.formatter}
           onCancelReply={this.props.onCancelReply}

src/widgets/image-preview.jsx

@@ -74,7 +74,6 @@ export default class ImagePreview extends React.PureComponent {
             messagePrompt="add_image_caption"
             acceptBlank={true}
             tinode={this.props.tinode}
-            viewportWidth={this.props.viewportWidth}  // Used by `formatter`.
             replyTo={this.props.replyTo}
             formatter={this.props.formatter}
             onCancelReply={this.props.onCancelReply}