Incorrect value in error message from GenericListArray::try_new_from_array_data

[jhorstmann]

Describe the bug
The error message should report the number of buffers instead of the arrays length:

if data.buffers().len() != 1 {
    return Err(ArrowError::InvalidArgumentError(
        format!("ListArray data should contain a single buffer only (value offsets), had {}",
                data.len())));
}

To Reproduce
Try to create a ListArray using ArrayDataBuilder and make_array, but forgetting to add a buffer.

Expected behavior
Error message should contain the actual number of buffers.