Bug 42013: Fix missing confirmation dialog for "Remove all reserves"

- The confirmDelete dialog for removing all reserves from a course
  was bound as a click handler on the #rm_items form element, which
  is never directly clicked by the user
- The #rm_items_button click handler called .submit() on the form
  without checking confirmDelete first, bypassing the confirmation
- Move the confirmDelete check into the #rm_items_button click
  handler and remove the dead #rm_items click handler

Test plan:
- Enable UseCourseReserves system preference (should be enabled in ktd)
- Create a course (or use the existing one) and add at least one reserve
  to it
- On the course details page, click "Remove all reserves"
- Observe the form submits immediately without confirmation
- Apply patch
- Repeat the steps above
- Verify a confirmation dialog now appears
- Click cancel and verify the reserves are not removed
- Click "Remove all reserves" again, confirm, and verify
  the reserves are removed

Signed-off-by: Roman Dolny <roman.dolny@jezuici.pl>
Signed-off-by: Brendan Lawlor <blawlor@clamsnet.org>
Signed-off-by: Pedro Amorim <pedro.amorim@openfifth.co.uk>

koha-tmpl/intranet-tmpl/prog/en/modules/course_reserves/course-details.tt

@@ -373,7 +373,9 @@
         $(document).ready(function () {
             $("#rm_items_button").on("click", function (e) {
                 e.preventDefault();
-                $("#rm_items").submit();
+                if (confirmDelete(_("Are you sure you want to remove all items from the course?"))) {
+                    $("#rm_items").submit();
+                }
             });
 
             var rtable = $("#course_reserves_table").kohaTable(
@@ -392,10 +394,6 @@
                 }
             });
 
-            $("#rm_items").click(function () {
-                return confirmDelete(_("Are you sure you want to remove all items from the course?"));
-            });
-
             $("#delete_course").on("submit", function () {
                 return confirmDelete(course_reserves_size > 0 ? i18n.are_you_sure_items : i18n.are_you_sure_no_item);
             });