Webform view has null values for structure array keys entity_type and field

Lines 111-125 in VboExportBase.php assumes that $field->options['entity_type'] and $field->options['entity_field'] will be populated and they are not for my webform view. This will give us errors saying these values are undefined - sorry deleted logs so I don't have it handy. I won't be able to supply a patch till tonight but just adding a isset, removes the errors:

    if (empty($structure)) {
      foreach ($this->view->field as $id => $field) {
        // Skip Views Bulk Operations field and excluded fields.
        if ($field->options['plugin_id'] === 'views_bulk_operations_bulk_form' || $field->options['exclude']) {
          continue;
        }
        $structure[$id] = [
          'id' => $id,
          'label' => $field->options['label'],
          'entity_type' => isset($field->options['entity_type']) ? $field->options['entity_type'] : '',
          'field' => isset($field->options['entity_field']) ? $field->options['label'] : '',
          'plugin_id' => $field->options['plugin_id'],
        ];
      }
    }