DRY-up conditionally creating callback tasks

This removes 3 duplicate instances of the same code, which is still
tested implicitly via test_process_ses_receipt_tasks [1]. In the
next commit we'll make this test more explicit, to reflect that it's
now being reused elsewhere and shouldn't change arbitrarily.

We do lose the "print" statement from the command instance of the
code, but I think that's a very tolerable loss.

[1]: 16ec8ccb8a/tests/app/celery/test_process_ses_receipts_tasks.py (L94)

app/celery/nightly_tasks.py

@@ -10,10 +10,6 @@ from sqlalchemy.exc import SQLAlchemyError
 
 from app import notify_celery, zendesk_client
 from app.aws import s3
-from app.celery.service_callback_tasks import (
-    create_delivery_status_callback_data,
-    send_delivery_status_to_service,
-)
 from app.config import QueueNames
 from app.cronitor import cronitor
 from app.dao.fact_processing_time_dao import insert_update_processing_time
@@ -27,9 +23,6 @@ from app.dao.notifications_dao import (
     dao_timeout_notifications,
     delete_notifications_older_than_retention_by_type,
 )
-from app.dao.service_callback_api_dao import (
-    get_service_delivery_status_callback_api_for_service,
-)
 from app.models import (
     EMAIL_TYPE,
     KEY_TYPE_NORMAL,
@@ -39,6 +32,9 @@ from app.models import (
     FactProcessingTime,
     Notification,
 )
+from app.notifications.notifications_ses_callback import (
+    check_and_queue_callback_task,
+)
 from app.utils import get_london_midnight_in_utc
 
 
@@ -126,12 +122,7 @@ def timeout_notifications():
             dao_timeout_notifications(current_app.config.get('SENDING_NOTIFICATIONS_TIMEOUT_PERIOD'))
 
         for notification in notifications:
-            # queue callback task only if the service_callback_api exists
-            service_callback_api = get_service_delivery_status_callback_api_for_service(service_id=notification.service_id)  # noqa: E501
-            if service_callback_api:
-                encrypted_notification = create_delivery_status_callback_data(notification, service_callback_api)
-                send_delivery_status_to_service.apply_async([str(notification.id), encrypted_notification],
-                                                            queue=QueueNames.CALLBACKS)
+            check_and_queue_callback_task(notification)
 
         current_app.logger.info(
             "Timeout period reached for {} notifications, status has been updated.".format(len(notifications)))