Support parsing IDs from VIAF's German interface URLs

src/enums/MDNodaRepository.php

@@ -813,6 +813,7 @@ public function validateId(string $id):string|false {
             ]),
             self::viaf      => self::validateNumericId($id, [
                 'https://viaf.org/viaf/',
+                'https://viaf.org/de/viaf/',
                 'http://viaf.org/viaf/',
             ]),
             self::wikidata  => self::validateWikidataId($id),