Draft stub control locations for rpc checksums

[joe-redpanda]

Backports Required

• [ ] none - not a bug fix
• [ ] none - this is a backport
• [ ] none - issue does not exist in previous branches
• [ ] none - papercut/not impactful enough to backport
• [ ] v25.1.x
• [ ] v24.3.x
• [ ] v24.2.x

Release Notes

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[vbotbuildovich]

CI test results

test results on build#67285

test_class	test_method	test_arguments	test_kind	job_url	test_status	passed	reason
DataMigrationsApiTest	test_creating_and_listing_migrations		ducktape	https://buildkite.com/redpanda/redpanda/builds/67285#01976609-ebc0-488c-bbbe-f3d7e9538b56	FLAKY	20/21	upstream reliability is '99.67532467532467'. current run reliability is '95.23809523809523'. drift is 4.43723 and the allowed drift is set to 50. The test should PASS
LeadershipPinningTest	test_leadership_pinning_sanctions		ducktape	https://buildkite.com/redpanda/redpanda/builds/67285#01976609-ebbf-4ad7-89ec-73d51375e0cb	FLAKY	20/21	upstream reliability is '100.0'. current run reliability is '95.23809523809523'. drift is 4.7619 and the allowed drift is set to 50. The test should PASS
TxUpgradeTest	upgrade_does_not_change_tx_coordinator_assignment_test		ducktape	https://buildkite.com/redpanda/redpanda/builds/67285#01976608-d091-4315-a224-4b097065ae83	FLAKY	20/21	upstream reliability is '95.48022598870057'. current run reliability is '95.23809523809523'. drift is 0.24213 and the allowed drift is set to 50. The test should PASS