Unable to add swagger-ui index as index in v3

[karisN]

Description

Unable to service swagger ui as index in v3
Flask app

app = connexion.App(
    __name__,
    specification_dir="./openapi/",
)
app.add_api(
    "openapi.yaml",
    pythonic_params=True,
    strict_validation=True,
    validator_map=validators.VALIDATOR_MAP,
    swagger_ui_options=SwaggerUIOptions(
        swagger_ui_path="/",
        swagger_ui_config={"showCommonExtensions": True},
    ),
    **additional_kwargs,
)

Expected behaviour

It serves swagger index as index

Actual behaviour

lib/python3.10/site-packages/connexion/middleware/swagger_ui.py:152: in add_swagger_ui
    self.router.add_route(methods=["GET"], path=console_ui_path, endpoint=redirect)
/lib/python3.10/site-packages/starlette/routing.py:802: in add_route
    route = Route(


    def __init__(
        self,
        path: str,
        endpoint: typing.Callable[..., typing.Any],
        *,
        methods: typing.Optional[typing.List[str]] = None,
        name: typing.Optional[str] = None,
        include_in_schema: bool = True,
    ) -> None:
>       assert path.startswith("/"), "Routed paths must start with '/'"
E       AssertionError: Routed paths must start with '/'

[karisN]

Actually, I don't think my propose PR fixes most of the issues if you're adding apis with a base path of "/" as well.
It'll get process twice, once by RouterMiddleware, then by SwaggerUIMiddleware, instead of a centralize list of routes putting the "/" at the end.

Thoughts from anyone who wants to serve swagger-ui at root?