omni-node: --dev sets manual seal and allows --chain to be set #7238

Job	Run time
preflight / preflight	38s
preflight / ci-versions	1m 1s
test-full-crypto-feature	2m 51s
cargo-check-all-crate-macos	11m 28s
cargo-check-benches (master)	20m 44s
cargo-check-each-crate (1)	19m 57s
cargo-check-benches (current)	20m 41s
test-frame-ui	46m 38s
cargo-check-each-crate (2)	21m 23s
test-node-metrics	8m 17s
cargo-check-each-crate (3)	9m 27s
cargo-check-each-crate (4)	20m 38s
cargo-check-each-crate (5)	26m 33s
cargo-check-each-crate (6)	14m 55s
cargo-check-each-crate (7)	30m 54s
test-frame-examples-compile-to-wasm	3m 10s
test-deterministic-wasm	6m 21s
check-tracing	2m 31s
check-metadata-hash	6m 10s
node-bench-regression-guard	12s
All test misc tests passed	1s
	4h 34m 30s

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