fix(trigger): handle missing subscription constructor in trigger subscription builder

- Updated the `TriggerSubscriptionBuilderService` to return an empty dictionary when the subscription constructor is not available, improving robustness in subscription handling.

api/services/trigger/trigger_subscription_builder_service.py

@@ -385,7 +385,7 @@ class TriggerSubscriptionBuilderService:
             credentials=masked_credentials(
                 schemas=controller.get_credentials_schema(credential_type),
                 credentials=entity.credentials,
-            ),
+            ) if controller.get_subscription_constructor() else {},
         )
 
     @classmethod