fix: send notification only when person exists

Refs: PT-1946

Author: mhieta

occurrences/notification_services.py

@@ -147,7 +147,7 @@ def translation(field_translation_map: object, language=None):
     if (
         NOTIFICATION_TYPE_EMAIL in notification_type
         and notification_template_id
-        and person.email_address
+        and person and person.email_address
     ):
         context = {
             "person": person,