Adds `onchain_locksroot` to our_state/partner_state in
    ContractReceiveChannelNew's channel_state object.

def _add_onchain_locksroot_to_channel_new_state_changes(
        storage: SQLiteStorage,
) -> None:
    """ Adds `onchain_locksroot` to our_state/partner_state in
    ContractReceiveChannelNew's channel_state object. """
    batch_size = 50
    batch_query = storage.batch_query_state_changes(
        batch_size=batch_size,
        filters=[
            ('_type', 'raiden.transfer.state_change.ContractReceiveChannelNew'),
        ],
    )
    for state_changes_batch in batch_query:
        updated_state_changes = list()
        for state_change in state_changes_batch:
            state_change_data = json.loads(state_change.data)

            channel_state = state_change_data['channel_state']
            msg = 'v18 state changes cant contain onchain_locksroot'
            assert 'onchain_locksroot' not in channel_state['our_state'], msg

            msg = 'v18 state changes cant contain onchain_locksroot'
            assert 'onchain_locksroot' not in channel_state['partner_state'], msg

            channel_state['our_state']['onchain_locksroot'] = serialize_bytes(EMPTY_MERKLE_ROOT)
            channel_state['partner_state']['onchain_locksroot'] = serialize_bytes(
                EMPTY_MERKLE_ROOT,
            )

            updated_state_changes.append((
                json.dumps(state_change_data),
                state_change.state_change_identifier,
            ))
        storage.update_state_changes(updated_state_changes)