message: vkcom/vkui#894: Extract Gallery controller logic into separate component
diff: this.state = {
  slideIndex: 0,
  - draggable: true
  + isDraggable: true
  }
  }
  render () {
  - const { draggable, slideIndex } = this.state
  + const { isDraggable, slideIndex } = this.state
  return (
  <View activePanel="gallery">
  <Panel id="gallery">
  align="center"
  style={{ height: 150 }}
  slideIndex={slideIndex}
  - // TODO: (() => {})
  - onChange={draggable ? slideIndex => this.setState({slideIndex}) : (() => {})}
  + onChange={slideIndex => this.setState({slideIndex})}
  + isDraggable={isDraggable}
  >
  <div style={{ backgroundColor: 'var(--destructive)' }} />
  <div style={{ backgroundColor: 'var(--button_commerce_background)' }} />
  <div style={{ backgroundColor: 'var(--accent)' }} />
  </Gallery>
  - <Checkbox checked={draggable} onChange={e => this.setState({ draggable: e.target.checked })}>
  - draggable
  + <FormItem>
  + <Checkbox checked={isDraggable} onChange={e => this.setState({ isDraggable: e.target.checked })}>
  + isDraggable
  </Checkbox>
  + </FormItem>
  <FormItem>
  - <Button size='l' stretch onClick={() => this.setState({ slideIndex: (slideIndex + 1) % 3 })}>
  + <Button size='l' stretched onClick={() => this.setState({ slideIndex: (slideIndex + 1) % 3 })}>
  Next slide
  </Button>
  </FormItem>
  