FileField Model validation doesn't work with default resolvers

There are many ways to to validations, one of them is through a custom clean method override on the django model or on the model fields themselves. We have a use case, for a FileAttachment model, where we want to ensure that the file has certain properties. (Also we allow either a file to be attached or an external url to be set)

This used to work well, but with some of the "recent" changes (we're upgrading from ~0.22.0), this does not work anymore.

Example:

    def clean(self) -> None:
        if not bool(self.file) ^ bool(self.external_url):
            # Either both or none of file/external_url is set => error
            raise ValidationError(
                "Exactly one of file and external_url have to be set"
            )

This causes an issue with create mutations because the resolver code looks like this:

    # manager create overrides. This also ensures support for proxy-models.
    instance = model._default_manager.create(**create_kwargs)

    # Now that the instance has been created, go and assign
    # files and many2many fields.
    if files:
        for file_field, value in files:
            file_field.save_form_data(instance, value)
        instance.save()

Here, the model is saved first, and then the files are added. I understand the reasoning for doing this for M2M, but file fields could be set before the save() call, right?

System Information

Operating system: Mac
Strawberry version (if applicable): strawberry-graphql[cli]==0.235.0 strawberry-graphql-django==0.44.2

Additional Context

Same for 0.43.0
I worked around it by moving this validation to the mutation itself

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strawberry-graphql / strawberry-django