[pallet-staking] Bound all storage #2738

Job	Run time
preflight / preflight	46s
preflight / ci-versions	1m 10s
cargo-check-benches (master)	5m 39s
cargo-check-benches (current)	5m 32s
test-frame-ui	25m 14s
test-full-crypto-feature	2m 39s
cargo-check-each-crate (1)	7m 17s
test-node-metrics	5m 43s
cargo-check-each-crate (2)	7m 11s
cargo-check-all-crate-macos	9m 33s
cargo-check-each-crate (3)	5m 43s
cargo-check-each-crate (4)	6m 51s
cargo-check-each-crate (5)	6m 25s
cargo-check-each-crate (6)	6m 22s
cargo-check-each-crate (7)	5m 53s
test-frame-examples-compile-to-wasm	2m 58s
node-bench-regression-guard	6s
check-tracing	0s
check-metadata-hash	0s
test-deterministic-wasm	5m 13s
All test misc tests passed	1s
	1h 50m 16s

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