`custody_bits_blocks` in `Attestation`

[ericsson49]

Attestation had custody_bits_blocks:

custody_bits_blocks: List[Bitlist[MAX_VALIDATORS_PER_COMMITTEE], MAX_SHARD_BLOCKS_PER_ATTESTATION]

It's used by is_valid_fraud_proof. Looks like it was dropped during recent merge: it's missing here. But is present here.

[ericsson49]

As @jrhea pointed out it's dropped by intention. So, it looks like is_valid_fraud_proof has not been updated appropriately