message: Fix modal buttons not being disabled by disabling them
  Looks like this was just a missed block of code, but also the important bit.
  Fixes
diff: @@ -161,7 +161,9 @@ export default class ModalWidgetDialog extends React.PureComponent<IProps, IStat
  this.state.messaging.notifyModalWidgetButtonClicked(def.id);
  };
  - return <AccessibleButton key={def.id} kind={kind} onClick={onClick}>
  + const isDisabled = this.state.disabledButtonIds.includes(def.id);
  +
  + return <AccessibleButton key={def.id} kind={kind} onClick={onClick} disabled={isDisabled}>
  { def.label }
  </AccessibleButton>;
  });
  