[BUG] Resolvers called even when schemas are created via __init__

[crbunney]

Pydantic allows you to create model instances by explicitly passing values directly to the model via the __init__ method (see Basic model usage).

Generally speaking, the same can be done with ninja, except when the Schema defines resolvers, which run even though an explicit value has already been passed to the instance, and cause a ValidationError.

In my case, I want to manually create instances so that I can easily write unit tests for the schema without having to create Django model instances that are costly and complex to setup.

Seems like it's a similar issue, or even the same issue, as reported in #871

How to reproduce
Run the test code using pytest:

import django.db.models
from django.db.models import JSONField
from ninja import Schema


class SimplifiedExample(django.db.models.Model):
    json_data = JSONField()

    def __getitem__(self, item: str) -> Any:
        return self.json_data[item]


class SimplifiedExampleSchema(Schema):
    foo: str
    bar: str

    @staticmethod
    def resolve_foo(obj: SimplifiedExample) -> str:
        return obj["foo"]

    @staticmethod
    def resolve_bar(obj: SimplifiedExample) -> str:
        return obj["bar"]


class TestSimplifiedExampleSchema:
    def test_example(self):
        SimplifiedExampleSchema(foo="foo", bar="bar")

Expected Result
The SimplifiedExampleSchema instance is created without error

Actual Result
A ValidationError is raised & pytest produces output similar to this:

E       pydantic_core._pydantic_core.ValidationError: 2 validation errors for SimplifiedExampleSchema
E       foo
E         Error extracting attribute: KeyError: 'foo' [type=get_attribute_error, input_value=<DjangoGetter: {'foo...bar': 'bar'}>, input_type=DjangoGetter]
E           For further information visit https://errors.pydantic.dev/2.10/v/get_attribute_error
E       bar
E         Error extracting attribute: KeyError: 'bar' [type=get_attribute_error, input_value=<DjangoGetter: {'foo...bar': 'bar'}>, input_type=DjangoGetter]
E           For further information visit https://errors.pydantic.dev/2.10/v/get_attribute_error

Versions:

• Python version: 3.10.16
• Django version: 4.2.17
• Django-Ninja version: 1.3.0
• Pydantic version: 2.10.3