refactor kontor-api to use SQLAlchemy 2.0 features for mapping fields

(cherry picked from commit e57abdbef7e13e3880738cd639225df5db0c37be)

kontor-api/src/db/repository/comics/artist.py

@@ -36,11 +36,12 @@ def get_artist_details(artist: Artist) -> ArtistDetailResponse:
     )
     return response
 
-def update_artist(add_artist: AddArtist, artist_id: str, db: Session) -> Artist:
+def update_artist(add_artist: AddArtist, artist_id: str, db: Session) -> Optional[Artist]:
     logger.info("update artist")
     artist: Optional[Artist] = db.get(Artist, artist_id)
-    artist.name = add_artist.name
-    db.add(artist)
-    db.commit()
-    db.refresh(artist)
+    if artist is not None:
+        artist.name = add_artist.name
+        db.add(artist)
+        db.commit()
+        db.refresh(artist)
     return artist