Explicitly overriding DEFAULT_AUTO_FIELD changes Django's behavior

[brianhelba]

From #263 (comment) :

DEFAULT_AUTO_FIELD, where settings.is_overridden('DEFAULT_AUTO_FIELD') is used in django/django@d29a9ed/django/db/models/base.py#L1308, which is True, although not overridden / defined explicitly.
Ref: docs.djangoproject.com/en/3.2/releases/3.2/#customizing-type-of-auto-created-primary-keys (models.W042)