Fixes for track management

tests/integration.rs

@@ -70,6 +70,10 @@ impl MetadataProvider for MockProvider {
     async fn get_release_tracks(&self, _release_mbid: &str) -> TagResult<Vec<shanty_tag::provider::ReleaseTrack>> {
         Ok(vec![])
     }
+
+    async fn get_artist_release_groups(&self, _artist_mbid: &str) -> TagResult<Vec<shanty_tag::provider::ReleaseGroupEntry>> {
+        Ok(vec![])
+    }
 }
 
 async fn test_db() -> Database {