message: Generate previews for rooms when the option changes
  Fixes
  This likely regressed in when the message preview information was made state, and the component wasn't updating the preview when the control flags changed.
diff: @@ -120,6 +120,12 @@ export default class RoomTile extends React.PureComponent<IProps, IState> {
  return !this.props.isMinimized && this.props.showMessagePreview;
  }
  + public componentDidUpdate(prevProps: Readonly<IProps>, prevState: Readonly<IState>) {
  + if (prevProps.showMessagePreview !== this.props.showMessagePreview && this.showMessagePreview) {
  + this.setState({messagePreview: this.generatePreview()});
  + }
  + }
  +
  public componentDidMount() {
  // when we're first rendered (or our sublist is expanded) make sure we are visible if we're active
  if (this.state.selected) {
  