Dialog for cart renewal, async task without page refresh (#5148)

* async_task: deduplicate response handling code

* extend cart without full page reload

* update dialog markup

* fix error response from CartExtend

* refactor asynctask, make sure waitingDialog.show() re-initializes dialog contents

* add cart expiry notification

* add aria references to other dialogs

* improve error handling

* fix error if max_extend=None

* different message for expiring soon and expired carts

* refactor dialog css

* add classes to further dialog elements

* switch extend-cart-dialog and loadingmodal to <dialog>

* Backport simple_block_tag from Django 5.2

* Use simple_block_tag for {% dialog %} tag

* add alertdialog role

* Update src/pretix/static/pretixbase/scss/_dialogs.scss

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* fix mobile dialog styles not being overwritten

* asynctask dialog: prevent close by escape on chrome

* remove dynamic aria-live from #cart-deadline

dynamic aria-live is generally not well supported and as we have the dialog now anyways, we can remove it

* move continue-button to right

* Update src/pretix/static/pretixpresale/js/ui/cart.js

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* Fix CSS for old-style dialog

* fix heading display/level

* align dialogs at the top as they originally were

* fix </div> from merge-conflict

* fix missing grow for dialog-content

* improve cart-extend-button ui

* do not show cart-extend-dialog onload

* improve message if 0 minutes

* do not save messae in session if ajax_dont_redirect

* add ajax_dont_redirect to async_task_check_url

* improve draw_deadline to only update #cart-deadline if necessary

* add renew-confirmation-message

---------

Co-authored-by: Richard Schreiber <schreiber@rami.io>
Co-authored-by: Raphael Michel <michel@rami.io>

src/pretix/presale/views/cart.py

@@ -542,8 +542,14 @@ class CartExtendReservation(EventViewMixin, CartActionMixin, AsyncAction, View):
     task = extend_cart_reservation
     known_errortypes = ['CartError']
 
+    def _ajax_response_data(self, value):
+        if isinstance(value, dict):
+            return value
+        else:
+            return {}
+
     def get_success_message(self, value):
-        if value > 0:
+        if value['success'] > 0:
             return _('Your cart timeout was extended.')
 
     def post(self, request, *args, **kwargs):
@@ -561,7 +567,7 @@ class CartAdd(EventViewMixin, CartActionMixin, AsyncAction, View):
     def get_success_message(self, value):
         return _('The products have been successfully added to your cart.')
 
-    def _ajax_response_data(self):
+    def _ajax_response_data(self, value):
         cart_id = get_or_create_cart_id(self.request)
         return {
             'cart_id': cart_id,