code: private function getItemData(RunnerServiceContext $context, $itemRef)
      {
          $this->getRunnerService()->assertQtiRunnerServiceContext($context);
  
          $itemData = $this->getRunnerService()->getItemData($context, $itemRef);
          $itemDataVariable = $this->getRunnerService()->getItemVariableElementsData($context, $itemRef);
          $responses = $itemData['data']['responses'];
  
          foreach (array_keys($responses) as $responseId) {
              if (array_key_exists($responseId, $itemDataVariable)) {
                  $itemData['data']['responses'][$responseId] = array_merge(...[
                      $responses[$responseId],
                      $itemDataVariable[$responseId],
                  ]);
              }
          }
  
          return $itemData;
      }
docs: Returns the itemData, extending with the variable elements
  
  @param RunnerServiceContext $context
  @param string $itemRef
  @return array
  @throws \common_exception_InvalidArgumentType
  @throws \common_Exception