Fix soundness bug in aggregator pi datahash

[zhenfeizhang]

Description

constraint

// 3 batch_data_hash and chunk[i].pi_hash use a same chunk[i].data_hash when
// chunk[i] is not padded
//
// batchDataHash = keccak(chunk[0].dataHash || ... || chunk[k-1].dataHash)
//
// chunk[i].piHash =
//     keccak(
//        &chain id ||
//        chunk[i].prevStateRoot ||
//        chunk[i].postStateRoot ||
//        chunk[i].withdrawRoot  ||
//        chunk[i].datahash)

was implemented incorrectly. The one gets implemented was

// 8. batch data hash is correct w.r.t. its RLCs

This PR fixes this issue.

Issue Link

[link issue here]

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Contents

• [item]

Rationale

[design decisions and extended information]

How Has This Been Tested?

tested mock prover with mock chunks

cargo test --release

[zhenfeizhang]

closed as integrated to #712