Add fix for empty noda references in fetching tags from Wikidata

src/NodaWikidataFetcher.php

@@ -1234,6 +1234,8 @@ final class NodaWikidataFetcher {
                 throw new Exception("Unknown URL prefix for: " . $vocabName);
             }
 
+            if (empty($nodaId)) continue;
+
             $noda_link = self::URL_PREFIXES_PLACES_NODA_SOURCE[$vocabName] . $nodaId;
 
             $insertNodaTagStmt->bind_param("isssssss", $tag_id, $vocabName, $nodaId, $noda_link, $erfasst_von, $nodaId, $noda_link, $erfasst_von);