fix bug reading of collections from database doesn't work

Classes/Controller/MetadataController.php

@@ -464,7 +464,7 @@ private function parseCollections(int $i, $value, array &$metadata) : void
  foreach ($value as $entry) {
  $collection = $this->collectionRepository->findOneByIndexName($entry);
  if ($collection) {
- $metadata[$i]['collection'][$j] = $collection->getLabel() ? : '';
+ $metadata[$i]['collection'] = $collection->getLabel() ? : '';
  $j++;
  }
  }