Serialise service, API keys and permissions

By serialising these straight away we can:
- not go back to the database later, potentially closing the connection
  sooner
- potentially cache the serialised data, meaning we don’t touch the
  database at all

app/notifications/process_notifications.py

@@ -123,7 +123,6 @@ def persist_notification(
         template_version=template_version,
         to=recipient,
         service_id=service.id,
-        service=service,
         personalisation=personalisation,
         notification_type=notification_type,
         api_key_id=api_key_id,

app/notifications/validators.py

@@ -90,7 +90,7 @@ def service_can_send_to_recipient(send_to, key_type, service, allow_whitelisted_
 
 
 def service_has_permission(notify_type, permissions):
-    return notify_type in [p.permission for p in permissions]
+    return notify_type in permissions
 
 
 def check_service_has_permission(notify_type, permissions):
@@ -137,7 +137,7 @@ def check_if_service_can_send_to_number(service, number):
     if (
         # if number is international and not a crown dependency
         international_phone_info.international and not international_phone_info.crown_dependency
-    ) and INTERNATIONAL_SMS_TYPE not in [p.permission for p in service.permissions]:
+    ) and INTERNATIONAL_SMS_TYPE not in service.permissions:
         raise BadRequestError(message="Cannot send to international mobile numbers")
     else:
         return international_phone_info