Filter not working for answer bot

I am trying to limit the scope of articles suggested by the answer bot by following the instructions here https://support.zendesk.com/hc/en-us/articles/229167008#topic_usl_bbq_mx

Unfortunately this does not work:

<script type="text/JavaScript">
window.zESettings = {
  webWidget: {
    helpCenter: {
      filter: {
        label_names: 'my-label'
      }
    }
  }
};
</script>

I even tried changing helpCenter to answerBot but that didn't make a difference.

<script type="text/JavaScript">
window.zESettings = {
  webWidget: {
    answerBot: {
      filter: {
        label_names: 'my-label'
      }
    }
  }
};
</script>