Omni-node: fix manual seal + asset hub polkadot scenario

[serban300]

When starting an asset hub polkadot node with manual seal:

polkadot-parachain --chain asset-hub-polkadot --dev-block-time 3000 --tmp

We get errors that go like:

2024-10-04 20:40:11 [Parachain] ❗️ Inherent extrinsic returned unexpected error: Error at calling runtime api: Execution failed: Execution aborted due to trap: wasm trap: wasm `unreachable` instruction executed
WASM backtrace:
error while executing at wasm backtrace:
    0: 0x1be1 - <unknown>!rust_begin_unwind
    1: 0x199e - <unknown>!core::panicking::panic_fmt::h3ab5417155b7ba3b
    2: 0x16c3 - <unknown>!core::result::unwrap_failed::h9bf99bca88ba05dc
    3: 0x3b9e4 - <unknown>!<cumulus_pallet_parachain_system::pallet::Call<T> as frame_support::traits::dispatch::UnfilteredDispatchable>::dispatch_bypass_filter::hb411780f0f813d4a
    4: 0x9a150 - <unknown>!<shell_runtime::Call as sp_runtime::traits::Dispatchable>::dispatch::hfa16958ca768b7fa
    5: 0x60b70 - <unknown>!frame_executive::Executive<System,Block,Context,UnsignedValidator,AllPallets,COnRuntimeUpgrade>::apply_extrinsic::h665bdef660f803fa
    6: 0x5efb3 - <unknown>!BlockBuilder_apply_extrinsic. Dropping.    
2024-10-04 20:40:11 [Parachain] panicked at 'set_validation_data inherent needs to be present in every block!', /build/pallets/parachain-system/src/lib.rs:135:13  

I think the issue is that the version of the code that is in the chainspec is outdated and probably the Parachain data inherent is incompatible with what we mock. When you actually run a parachain node it doesn't matter if the code in the spec is outdated, because it connects to the peers and gets the on-chain version. But when you run with manual seal, it tries to run the version that's in the spec.

So I think that the solution is to update the asset-hub-polkadot chainspec: https://github.com/paritytech/polkadot-sdk/blob/master/cumulus/parachains/chain-specs/asset-hub-polkadot.json using chain-spec-builder update-code.