Bug 14535: Update the supplier filter too

Bug 14535: Update the supplier filter too

The combobox on the left side of late orders is filled by sub
GetBooksellersWithLateOrders. The same change as in the first patch
must be made here to include suppliers with late orders without a
price.

Bonus: Sort the list.

Test plan:
[1] Run t/db_dependent/Bookseller.t.
[2] Go to late orders. Use the filter on suppliers.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Srdjan <srdjan@catalyst.net.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>