api: do not fail on missing title

src/authentic2_cut/apps.py

@@ -263,7 +263,11 @@ class AppConfig(django.apps.AppConfig):
             del serializer.fields['last_login']
 
             def get_gender(obj):
-                title = obj.attributes.title
+                attributes = obj.attributes
+                try:
+                    title = attributes.title
+                except AttributeError:
+                    return None
                 return {'Monsieur': 'male', 'Madame': 'female'}.get(title)
             serializer.get_gender = get_gender