Catch exception when downloadURL is not present

[janette]

dkan_datastore

public function get($useFileFetcher = FALSE, $runFileFetcher = TRUE): ?R {
    $node = $this->entityRepository->loadEntityByUuid('node', $this->uuid);
    if (!$node) {
      return NULL;
    }

    if ($useFileFetcher == TRUE) {
      return $this->getResourceFromFileFetcher($node, $runFileFetcher);
    }
    else {
      return new R($node->id(), $this->getResourceFilePathFromNode($node));
    }
  }

Unable to harvest datasets that use the accessURL instead