Gmoshkin/enforce proc name in rpc

Summary

• refactor: enforce explicit procedure name in rpc::network_call

• refactor: enforce explicit procedure name in ConnectionPool::call

• fix: remove unused step ShardingInit

• rename: stringify_cfunc -> proc_name

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• Close #...
• Cherry-pick to: none / 24.4 / 24.3 / 24.2
• Docs follow-up: not necessary / new issue