Drop nullability on Order.organizer and OrderPosition.organizer (#4278)

* Drop nullability on Order.organizer and OrderPosition.organizer

* Rebase migration and add autoclean

* Utilize new relationship for scopes

* Declare reverse noop

* Update src/pretix/base/migrations/0302_resolve_duplicate_codes_and_secrets.py

Co-authored-by: Martin Gross <gross@rami.io>

* Update src/pretix/base/migrations/0302_resolve_duplicate_codes_and_secrets.py

Co-authored-by: Martin Gross <gross@rami.io>

---------

Co-authored-by: Martin Gross <gross@rami.io>

src/pretix/base/models/orders.py

@@ -224,8 +224,6 @@ class Order(LockModel, LoggedModel):
         "Organizer",
         related_name="orders",
         on_delete=models.CASCADE,
-        null=True,
-        blank=True,
     )
     event = models.ForeignKey(
         Event,
@@ -329,7 +327,7 @@ class Order(LockModel, LoggedModel):
         default="line",
     )
 
-    objects = ScopedManager(OrderQuerySet.as_manager().__class__, organizer='event__organizer')
+    objects = ScopedManager(OrderQuerySet.as_manager().__class__, organizer='organizer')
 
     class Meta:
         verbose_name = _("Order")
@@ -2541,8 +2539,6 @@ class OrderPosition(AbstractPosition):
         "Organizer",
         related_name="order_positions",
         on_delete=models.CASCADE,
-        null=True,
-        blank=True,
     )
     order = models.ForeignKey(
         Order,
@@ -2599,7 +2595,7 @@ class OrderPosition(AbstractPosition):
         blank=True,
     )
 
-    all = ScopedManager(organizer='order__event__organizer')
+    all = ScopedManager(organizer='organizer')
     objects = ActivePositionManager()
 
     def __init__(self, *args, **kwargs):