feat(trigger): enhance trigger subscription handling with credential support

- Added `credentials` and `credential_type` parameters to various methods in `PluginTriggerManager`, `PluginTriggerProviderController`, and `TriggerManager` to support improved credential management for trigger subscriptions.
- Updated the `Subscription` model to include `parameters` for better subscription data handling.
- Refactored related services to accommodate the new credential handling, ensuring consistency across the trigger workflow.

api/models/trigger.py

@@ -71,6 +71,7 @@ class TriggerSubscription(Base):
         return Subscription(
             expires_at=self.expires_at,
             endpoint=parse_endpoint_id(self.endpoint_id),
+            parameters=self.parameters,
             properties=self.properties,
         )