[BUG] Python: When using a openapi specification only containing components and no apis, the setup.py is not generated correctly

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

I use a openapi specification similar to this:

When I generate the python code using the OpenAPI generator to create data objects (then used with RabbitMQ), the generated setup looks like this:
actual

# coding: utf-8

"""
comments blabla
"""  # noqa: E501
from setuptools import setup, find_packages  # noqa: H301

# To install the library, run the following
#
# python setup.py install
#
# prerequisite: setuptools
# http://pypi.python.org/pypi/setuptools
NAME = "openapi-client"
VERSION = "0.1.0"
PYTHON_REQUIRES = ">=3.7"

expected

# coding: utf-8

"""
comments blabla
"""  # noqa: E501
from setuptools import setup, find_packages  # noqa: H301

# To install the library, run the following
#
# python setup.py install
#
# prerequisite: setuptools
# http://pypi.python.org/pypi/setuptools
NAME = "openapi-client"
VERSION = "0.1.0"
PYTHON_REQUIRES = ">=3.7"

setup(
    name=NAME,
    version=VERSION,
    description="Test API",
    author="OpenAPI Generator community",
    author_email="team@openapitools.org",
    url="",
    keywords=["OpenAPI", "OpenAPI-Generator", "Test API"],
    install_requires=REQUIRES,
    packages=find_packages(exclude=["test", "tests"]),
    include_package_data=True,
    long_description_content_type='text/markdown',
    long_description="""\
    No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
    """,  # noqa: E501
    package_data={"openapi_client": ["py.typed"]},
)

openapi-generator version

All generators >= 7.0.0, worked with earlier versions

OpenAPI declaration file content or url

openapi: 3.0.3
info:
    title: 'Test API'
    version: '0.1.0'
paths: {}
components:
    schemas:
        TestRequest:
            type: object
            properties:
                requestId:
                    type: string
                pageSize:
                    type: integer
                    description: ...
                pageNumber:
                    type: integer
                    description: ...
            required:
                - requestId

Generation Details

Generation is then done in Docker

# Stage 1: Use openapi-generator to generate code
FROM openapitools/openapi-generator-cli:latest AS generator # any >v7.0.0 is the same behavior

COPY test-api-v1/ /local/test-api-v1/
# Generate openapi client
RUN bash /usr/local/bin/docker-entrypoint.sh generate -i /local/test-api-v1/openapi-specification.yml -g python -o local/openapi

Steps to reproduce

Just generate the code with the Generation Details and the OpenAPI declaration.

Related issues/PRs

I did not find any related issues. I was searching for ~ 10 hours to identify this issue.

Suggest a fix

I have already identified the problem. It is because the mustache file requires an API definition to generate the setup contents (see here)
Removing this filter for apis or/and latest should fix the problem. A current workaround is to add a dummy API, which is then not used.
I have no knowledge of mustache and its templating. So I can not help very much here

Read modules/openapi-generator/src/main/resources/python/setup.mustache, especially the filter around line 17, and compare it with generation from the provided components-only OpenAPI specification. Run the Docker generation command from the issue and confirm that setup.py includes the complete setup(...) contents without requiring a dummy API.