title: WooCommerce Webhooks Custom/Action not saving
body: <p>Every time you try and set a custom/action topic within webhooks <strong>(from WooCommerce > Settings > Webhooks)</strong> it would unset it as soon as you update your changes to the webhook. <em>In other words, it will undo your custom topic and return it back to 'Select an option' for the topic dropdown.</em></p>
  
  <p>Any help at all is appreciated. Thank you very much!</p>
  
  <p>edit: In addition to my comment below, I've also attempted to create my own custom topic via the following filter <code>woocommerce_webhook_topic_hooks</code>, however, it doesn't show within the dropdown list as an option.</p>
  
  <p>The below code runs from <code>functions.php</code> as with any WordPress hook..</p>
  
  <p><strong>Code</strong></p>
  
  <pre><code>function custom_woocommerce_webhook_topics( $topic ) {
      $topic['order.refunded'] = array(
          'woocommerce_process_shop_order_meta',
          'woocommerce_api_edit_order',
          'woocommerce_order_edit_status',
          'woocommerce_order_status_changed'
      );
  
      return $topic;
  }
  
  add_filter( 'woocommerce_webhook_topic_hooks', 'custom_woocommerce_webhook_topics', 10, 1 );
  </code></pre>
  
  <p>edit 2: Added more context</p>