chore: Cleanup database sessions (#10427)

Co-authored-by: John Bodley <john.bodley@airbnb.com>

superset/sql_lab.py

@@ -132,8 +132,7 @@ def session_scope(nullpool: bool) -> Iterator[Session]:
         )
     if nullpool:
         engine = sqlalchemy.create_engine(database_uri, poolclass=NullPool)
-        session_class = sessionmaker()
-        session_class.configure(bind=engine)
+        session_class = sessionmaker(bind=engine)
         session = session_class()
     else:
         session = db.session()