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/static/pretixcontrol/js/ui/main.js

@@ -51,32 +51,6 @@ function formatPrice(price, currency, locale) {
     }
 }
 
-var waitingDialog = {
-    show: function (message) {
-        "use strict";
-        $("#loadingmodal").find("h1").html(message);
-        $("body").addClass("loading");
-    },
-    hide: function () {
-        "use strict";
-        $("body").removeClass("loading");
-    }
-};
-
-var ajaxErrDialog = {
-    show: function (c) {
-        "use strict";
-        $("#ajaxerr").html(c);
-        $("#ajaxerr .links").html("<a class='btn btn-default ajaxerr-close'>"
-            + gettext("Close message") + "</a>");
-        $("body").addClass("ajaxerr");
-    },
-    hide: function () {
-        "use strict";
-        $("body").removeClass("ajaxerr");
-    }
-};
-
 var apiGET = function (url, callback) {
     $.getJSON(url, function (data) {
         callback(data);