downgrade grpc

[tvalentyn]

Fixes: #32324

Tested: apache/beam/actions/runs/10839063060/job/30078643883?pr=32446

One more run in flight: https://github.com/apache/beam/actions/runs/10840227044

GRPCIO issue: grpc/grpc#37710

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[tvalentyn]

R: @lostluck
cc: @shunping

[github-actions]

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[lostluck]

Tomorrow I'll look into ensuring the GoPortable tests run when these. Python deps change, to reduce a regression chance. Basically just needs to be the deps file here, and anything else in the portable python runner code.

[tvalentyn]

the dependency had an upper bound, so that we find sooner than later that an upgrade breaks us