backport/rpc-v2: Implement `archive_unstable_storageDiff` (stable2412) #15245

Job	Run time
preflight / preflight	42s
preflight / ci-versions	1m 1s
check-runtime-migration (westend)	6m 29s
check-runtime-migration (asset-hub-westend)	4m 52s
check-runtime-migration (bridge-hub-westend)	4m 19s
check-runtime-migration (collectives-westend)	4m 30s
check-runtime-migration (coretime-westend)	4m 9s
All runtime migrations passed	1s
	26m 3s

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