Returns a list for current batch stock.
Stock that is not assigned to any batch is returned under the variant's Unbatched batch (batch_number "Unbatched")
when the variant has one, otherwise with batch_id, batch_number, batch_created_date, expiration_date and
batch_barcode set to null. batch_number=Unbatched returns such stock; the other batch filters, including batch_id
with an Unbatched batch's id, do not match it. Rows of archived or deleted items are not listed.
Rows are returned in a stable order, so paging never repeats or skips a row: by the key
{location_id}-{variant_id}-{batch_id} ({location_id}-{variant_id} for stock without a batch), compared as text, not
as numbers. For example, location 10 comes before location 9.