Bug 15348: (follow-up) Fix modals to pre-set input with stored date

Bug 15348: (follow-up) Fix modals to pre-set input with stored date

Makes sure that when an estimated delivery day is edited using
the modals on the basket summary or late order pages, the
date input is pre-set to the stored estimated delivery date.

To test:
* Create some order lines with and without estimated delivery date set
* Make sure that on the basket summary the edit link comes up with an
  empty modal
* Close the basket
* Check that on late orders the dates are pre-filled incorrectly as well
* Apply patch
* Refresh basket summary and late order pages
* All edit links now should bring up the modal with the correct date filled in

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>