Fixed set call

src/submission/check_validity.py

@@ -100,4 +100,4 @@ def already_submitted_models(requested_models_dir: str) -> set[str]:
                     organisation, _ = info["model"].split("/")
                     users_to_submission_dates[organisation].append(info["submitted_time"])
 
-    return set(requested_models), users_to_submission_dates
+    return requested_models, users_to_submission_dates