Fix hash validation, update allowed code hashes list

[cboh4]

1. previously the code used String::from_utf8_lossy to convert the decoded hash bytes to a string. the fix replaces this with hex::encode.
2. In the original implementation, even if the mismatched hash was allowed by is_code_hash_allowed, the function would still return an error due to an unconditional error return following the check. This PR removes that redundant return statement, allowing processing to continue when the hash is explicitly allowed.
3. the allowed list of code hashes has been extended in ALLOWED_CONTRACT_CODE_HASH