Remove default suffix in GenericModel class

In some combinations of Python/Celery/Pydantic versions this would lead to:

_pickle.PicklingError: Can't pickle <class 'galaxy.schema.notifications.NotificationRecipientsIncoming'>: attribute lookup NotificationRecipientsIncoming on galaxy.schema.notifications failed

This is because the NotificationRecipientsIncoming dynamic model is not yet available in the module.
Removing the `Incoming` prefix will match the existing NotificationRecipients alias which is explicitly defined in the notifications module.

lib/galaxy/schema/generics.py

@@ -33,7 +33,7 @@ def __get_pydantic_core_schema__(cls, *args, **kwargs):
 
     @classmethod
     def __determine_suffix__(cls, params: Tuple[Type[Any], ...]) -> str:
-        suffix = "Incoming"
+        suffix = ""
         if params[0] is EncodedDatabaseIdField:
             suffix = "Response"
         elif params[0] is DecodedDatabaseIdField: