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/base/services/cart.py

@@ -1655,7 +1655,7 @@ def clear_cart(self, event: Event, cart_id: str=None, locale='en', sales_channel
 
 
 @app.task(base=ProfiledEventTask, bind=True, max_retries=5, default_retry_delay=1, throws=(CartError,))
-def extend_cart_reservation(self, event: Event, cart_id: str=None, locale='en', sales_channel='web', override_now_dt: datetime=None) -> None:
+def extend_cart_reservation(self, event: Event, cart_id: str=None, locale='en', sales_channel='web', override_now_dt: datetime=None) -> dict:
     """
     Resets the expiry time of a cart to the configured reservation time of this event.
     Limited to 11x the reservation time.
@@ -1672,7 +1672,7 @@ def extend_cart_reservation(self, event: Event, cart_id: str=None, locale='en',
             try:
                 cm = CartManager(event=event, cart_id=cart_id, sales_channel=sales_channel)
                 cm.commit()
-                return cm.num_extended_positions
+                return {"success": cm.num_extended_positions, "expiry": cm._expiry, "max_expiry_extend": cm._max_expiry_extend}
             except LockTimeoutException:
                 self.retry()
         except (MaxRetriesExceededError, LockTimeoutException):