Bug: Validation Error in Pydantic model with optional list

Description

Even the simplest model with an optional list appears to not work. Instead of generating a valid coverage including None and a random string, a validation error is raised. Worth noting that it seems to be making a list of list of str, rather than a list of string.

URL to code causing the issue

https://github.com/RLC92/polyfactory_error_submission

MCVE

from pydantic import BaseModel
from typing import Optional, List, Union # Note: Optional is included as I tried it as well, realize that it is also just a union.
from polyfactory.factories.pydantic_factory import ModelFactory

class ExampleModel(BaseModel):
    values: Union[List[str], None]

class ExampleModelFactory(ModelFactory):
    __model__ = ExampleModel

if __name__ == "__main__":
    print(list(ExampleModelFactory.coverage()))

Steps to reproduce

1. Install dependencies (I'm using 1.10.17 and polyfactory 2.16.0)
2. Run the example.
3. Get a validation failure in coverage:

pydantic.error_wrappers.ValidationError: 1 validation error for ExampleModel
values -> 0
  str type expected (type=type_error.str)

Screenshots

No response

Logs

No response

Release Version

2.16.0

Platform

[X] Linux
[ ] Mac
[ ] Windows
[ ] Other (Please specify in the description above)

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litestar-org / polyfactory

Bug: Validation Error in Pydantic model with optional list #559