cmake:python: stubgen timeout on macos intel

[Mizux]

On my macos I can't generate mypy file using stugen there is a timeout

trace

coming soon

[Mizux]

side topic: in bazel we are required to migrate from @rules_proto to @protobuf to generate python from .proto BUT the new rules do not generate mypy files -> potential regression in protobuf and cmake is impacted too ?