[BUG] Python asyncio tests are not closing API Client

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

openapi-generator version

7.9.0

OpenAPI declaration file content or url

https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml

Generation Details

Steps to reproduce

docker run --rm -v "${PWD}:/local" openapitools/openapi-generator-cli generate -i https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml -g python -p library=asyncio -o /local/out/python

python -m venv venv
pip install -r requirements.txt -r test-requirements.txt
pytest

Pytest fill give a warning for each API class similar to the following:

Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x7f39496c5160>                                                                                                                                                                                     

Related issues/PRs

Suggest a fix

For any of the TestXXXXXApi test classes, just replace the following:

    async def asyncTearDown(self) -> None:
        pass

with

    async def asyncTearDown(self) -> None:
        await self.api.api_client.close()

(for example for the PetStore API spec, it is test/test_pet_api.py:TestPetApi)

Generate the Python asyncio client from the PetStore spec using the listed Docker command, then inspect test/test_pet_api.py and its TestPetApi.asyncTearDown method. Ensure the generated API client is closed during teardown and run pytest to confirm the unclosed aiohttp client-session warnings are gone.