Empty series and slice mask functions column rather than row first

Hi!

I noticed when working with uneven MRI volumes that the order of rows and columns is not consistent throughout. In most parts of the repo the order is correctly row-major, but for creating empty series and slice masks the order is reversed to column-major. Is this intentional and if so why?

def create_empty_series_mask(series_data):
    ref_dicom_image = series_data[0]
    mask_dims = (
        int(ref_dicom_image.Columns),
        int(ref_dicom_image.Rows),
        len(series_data),
    )
    mask = np.zeros(mask_dims).astype(bool)
    return mask

def create_empty_slice_mask(series_slice):
    mask_dims = (int(series_slice.Columns), int(series_slice.Rows))
    mask = np.zeros(mask_dims).astype(bool)
    return mask

Would be happy to send a PR changing these methods to row-major as well.

Thanks!