mypy presubmit fails at HEAD with mypy 1.11+

[parthea]

See this build log which shows that mypy is failing at head with

google/api_core/grpc_helpers_async.py:157: error: Type application targets a non-generic function or class  [misc]
tests/asyncio/test_grpc_helpers_async.py:3[18](https://github.com/googleapis/python-api-core/actions/runs/10182615581/job/28165602524?pr=681#step:5:19): error: Type application targets a non-generic function or class  [misc]

The issue exists with mypy 1.11.0 and newer and started on July 19th

https://pypi.org/project/mypy/#history

[parthea]

@daniel-sanche Please could you take a look?

[daniel-sanche]

I put together a fix at #768, let me know what you think