omni-node: --dev sets manual seal and allows --chain to be set #7241

Job	Run time
preflight / preflight	42s
preflight / ci-versions	1m 2s
test-frame-ui	46m 16s
cargo-check-benches (master)	21m 8s
test-full-crypto-feature	2m 48s
cargo-check-benches (current)	21m 0s
test-node-metrics	8m 34s
cargo-check-all-crate-macos	11m 29s
cargo-check-each-crate (1)	18m 53s
cargo-check-each-crate (2)	19m 45s
cargo-check-each-crate (3)	8m 43s
cargo-check-each-crate (4)	17m 15s
cargo-check-each-crate (5)	24m 28s
cargo-check-each-crate (6)	15m 9s
cargo-check-each-crate (7)	26m 27s
test-frame-examples-compile-to-wasm	3m 4s
test-deterministic-wasm	6m 26s
check-tracing	2m 19s
check-metadata-hash	6m 11s
node-bench-regression-guard	12s
All test misc tests passed	1s
	4h 21m 52s

Provide feedback