Model subclass with __init_subclass__ doesn't get correct _meta instance

[Ben Beecher]

When defining and using a model mixin like so:

`
class ModelMixin(Model):

class Meta:

abstract = True

def init_subclass(cls) -> None:

super().init_subclass()
breakpoint()
cls._my_setup_func()

class TestModel(ModelMixin):

name = models.CharField(max_length=100)

`

The init_subclass call will be first called when the class is created here:
​https://github.com/django/django/blob/main/django/db/models/base.py#L120

However the meta is attached here:
​https://github.com/django/django/blob/main/django/db/models/base.py#L143

So during the init_subclass call you will have the superclass' meta object if you try to access it.