message: Small refactor buttongroup in React
diff: @@ -20,7 +20,7 @@ export class SurveyQuestionButtonGroup extends SurveyQuestionElementBase {
  getStateElement() {
  return this.question;
  }
  - render() {
  + renderElement() {
  const items = this.renderItems();
  return <div className={this.question.cssClasses.root}>{items}</div>;
  }
  @@ -44,7 +44,6 @@ export class SurveyButtonGroupItem extends SurveyElementBase<any, any> {
  public model: ButtonGroupItemModel;
  constructor(props: any) {
  super(props);
  - this.model = new ButtonGroupItemModel(this.question, this.item, this.index);
  }
  get index(): number {
  return this.props.index;
  @@ -58,7 +57,8 @@ export class SurveyButtonGroupItem extends SurveyElementBase<any, any> {
  getStateElement() {
  return this.item;
  }
  - public render() {
  + public renderElement() {
  + this.model = new ButtonGroupItemModel(this.question, this.item, this.index);
  const icon = this.renderIcon();
  const input = this.renderInput();
  const caption = this.renderCaption();
  