message: Allow modal widget buttons to be disabled when the modal opens
diff: @@ -63,7 +63,8 @@ export default class ModalWidgetDialog extends React.PureComponent<IProps, IStat
  private appFrame: React.RefObject<HTMLIFrameElement> = React.createRef();
  state: IState = {
  - disabledButtonIds: [],
  + disabledButtonIds: (this.props.widgetDefinition.buttons || []).filter(b => b.disabled)
  + .map(b => b.id),
  };
  constructor(props) {
  