Implement flat-encoding (pectra-devnet-4) #7522
Description
EIP-7251: max eb, change request to flat encoding ethereum/EIPs#8857
EIP-6110: deposits, change request to flat encoding ethereum/EIPs#8856
EIP-7002: withdrawals, change request to flat encoding ethereum/EIPs#8855
EIP-7685: change requests hash to flat hash
ethereum/EIPs#8854