Remove grpc from kwargs deprecation silence list

What does this MR do and why?

We no longer need to silence keyword-args-related deprecations from grpc. The issue was resolved by updating grpc to 1.42.
Cleaning up the "allow list", we are making the DeprecationToolkitEnv more strict.

More details in the issue.

How to set up and validate locally

CI-verified change, because DeprecationToolkitEnv is used in specs only.

MR acceptance checklist

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