[BUGFIX] Remove Score Filegroup out of configKeys

Because Score is not present in Branch v5.0.x.
Reintroduced missing Filegroup Audio as it was before. But was removed by Maintenance in this commit: #8427b4

Author: fschoelzel

Classes/Common/MetsDocument.php

@@ -1165,7 +1165,7 @@ protected function magicGetFileGrps(): array
                 'fileGrpThumbs',
                 'fileGrpDownload',
                 'fileGrpFulltext',
-                'fileGrpScore'
+                'fileGrpAudio'
             ];
 
             foreach ($configKeys as $key) {