Snowbridge Ethereum Deneb fork preparation (#3029)

- Prepares for the Deneb hardfork on Sepolia testnet on 31 January
(needs to be deployed to Rococo before then)
- Removes `beacon-minimal-spec` flag for simpler config
- Adds test comments

---------

Co-authored-by: Ron <yrong1997@gmail.com>
Co-authored-by: claravanstaden <Cats 4 life!>
Co-authored-by: Alistair Singh <alistair.singh7@gmail.com>

cumulus/parachains/runtimes/test-utils/src/lib.rs

@@ -33,7 +33,7 @@ use polkadot_parachain_primitives::primitives::{
 	HeadData, HrmpChannelId, RelayChainBlockNumber, XcmpMessageFormat,
 };
 use sp_consensus_aura::{SlotDuration, AURA_ENGINE_ID};
-use sp_core::Encode;
+use sp_core::{Encode, U256};
 use sp_runtime::{traits::Header, BuildStorage, Digest, DigestItem};
 use xcm::{
 	latest::{Asset, Location, XcmContext, XcmHash},
@@ -300,6 +300,10 @@ where
 		<Runtime as frame_system::Config>::RuntimeOrigin::root()
 	}
 
+	pub fn block_number() -> U256 {
+		frame_system::Pallet::<Runtime>::block_number().into()
+	}
+
 	pub fn origin_of(
 		account_id: AccountIdOf<Runtime>,
 	) -> <Runtime as frame_system::Config>::RuntimeOrigin {