Fix setting of user of profile in factory

When trying to create a profile without a preset user django complains
We always set a user in tests, which is why this was undiscovered

src/argus/notificationprofile/factories.py

@@ -76,7 +76,7 @@ class NotificationProfileFactory(factory.django.DjangoModelFactory):
     class Meta:
         model = models.NotificationProfile
 
-    user = factory.SubFactory(PersonUserFactory, user=factory.SelfAttribute("..timeslot"))
+    user = factory.LazyAttribute(lambda profile: profile.timeslot.user)
     timeslot = factory.SubFactory(TimeslotFactory)
     active = factory.Faker("boolean")