EVM node: fix transaction type encoding

Checklist

• Provide automatic testing.
• Add an item in the changelog
• Add a page in the doc

What

Use a compact hexadecimal encoding in JSON for the transaction type, e.g. 0x2 instead of 0x02 for EIP 1559.

Why

• The ethereum specification requires quantities to be compactly encoded in hex, see https://ethereum.org/en/developers/docs/apis/json-rpc/#quantities-encoding and https://ethereum.org/en/developers/docs/transactions/#typed-transaction-envelope.
• This is an issue for people that want to use the geth client.
• Potentially also an error with hardhat users.

How

Use correct encoding but support reading older one for backward compatibility.