introspect_token raises no-untyped-call violation in 1.6.6.20251220

Hello folks 👋 Thanks for your efforts on this open source project 🫶 We're experiencing a `mypy` issue after [updating `types-authlib` to 1.6.6.20251220](https://gitlab.com/biomedit/portal/-/merge_requests/2039). ## Bug behavior [Invoking the `introspect_token` method of the `AsyncOAuth2Client`](https://gitlab.com/biomedit/portal/-/blob/main/web/portal/dependencies.py?ref_type=heads#L108) raises a `[no-untyped-call]` violation. ## Expected behavior No typing exception is raised. ## Relevant logs - Log of the CI job: https://gitlab.com/biomedit/portal/-/jobs/12505414931.