fix: change misleading comment & remove redundant if statement

Author: AlexsanderHamir

litellm/router.py

@@ -5694,7 +5694,7 @@ def _set_model_group_info(  # noqa: PLR0915
         total_tpm: Optional[int] = None
         total_rpm: Optional[int] = None
         configurable_clientside_auth_params: CONFIGURABLE_CLIENTSIDE_AUTH_PARAMS = None
-        # Use set for O(1) provider lookups during iteration
+        # Use set for O(1) deduplication
         providers_set: set = set()
         model_list = self.get_model_list(model_name=model_group)
         if model_list is None: