fix: apply ruff formatting to _check_keys_and_notif_id

Fixes CI formatting failure introduced by the manual Sonar cognitive-
complexity fix (extracting the ignore-list/dedup check into its own
helper).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

orchestrator/activities/slot_manager.py

@@ -447,8 +447,9 @@ class SlotManager(SientiaMonitoring):
                 # Check if this group must be notified
                 if (
                     alert_type in receiver_group['contents']
-                    and notification_id not in ignore_list
+                    and self._check_keys_and_notif_id(
-                    and key not in already_added_keys
+                        notification_id, ignore_list, key, already_added_keys
+                    )
                     and self._check_levels_and_ignore_models_id(
                         notification, levels_list, ignore_models_id_list
                     )
@@ -484,6 +485,23 @@ class SlotManager(SientiaMonitoring):
         )
         return level_check and model_id_check
 
+    @staticmethod
+    def _check_keys_and_notif_id(notification_id, ignore_list, key, already_added_keys) -> bool:
+        """
+        Check if the key has already been added to the list of already added keys.
+
+        Args:
+            notification_id (str): The ID of the notification.
+            ignore_list (list): List of notification IDs to ignore.
+            key (str): The key to check.
+            already_added_keys (list[str]): List of keys that have already been added.
+
+        Returns:
+            bool: True if the key has not been added yet, False otherwise.
+
+        """
+        return notification_id not in ignore_list and key not in already_added_keys
+
     @activity.defn(name='store_notification_cache')
     def store_notification_cache(self, input_data: dict[str, Any]) -> None:
         """