Widget: Workaround for cookiebot issue

src/pretix/static/pretixpresale/js/widget/widget.js

@@ -857,7 +857,7 @@ var shared_iframe_fragment = (
     + '<svg width="256" height="256" viewBox="0 0 1792 1792" xmlns="http://www.w3.org/2000/svg"><path class="pretix-widget-primary-color" d="M1152 896q0-106-75-181t-181-75-181 75-75 181 75 181 181 75 181-75 75-181zm512-109v222q0 12-8 23t-20 13l-185 28q-19 54-39 91 35 50 107 138 10 12 10 25t-9 23q-27 37-99 108t-94 71q-12 0-26-9l-138-108q-44 23-91 38-16 136-29 186-7 28-36 28h-222q-14 0-24.5-8.5t-11.5-21.5l-28-184q-49-16-90-37l-141 107q-10 9-25 9-14 0-25-11-126-114-165-168-7-10-7-23 0-12 8-23 15-21 51-66.5t54-70.5q-27-50-41-99l-183-27q-13-2-21-12.5t-8-23.5v-222q0-12 8-23t19-13l186-28q14-46 39-92-40-57-107-138-10-12-10-24 0-10 9-23 26-36 98.5-107.5t94.5-71.5q13 0 26 10l138 107q44-23 91-38 16-136 29-186 7-28 36-28h222q14 0 24.5 8.5t11.5 21.5l28 184q49 16 90 37l142-107q9-9 24-9 13 0 25 10 129 119 165 170 7 8 7 22 0 12-8 23-15 21-51 66.5t-54 70.5q26 50 41 98l183 28q13 2 21 12.5t8 23.5z"/></svg>'
     + '</div>'
     + '<div class="pretix-widget-frame-inner" ref="frame-container" v-show="$root.frame_shown">'
-    + '<iframe frameborder="0" width="650" height="650" @load="iframeLoaded" '
+    + '<iframe frameborder="0" width="650" height="650" ref="iframe" @load="iframeLoaded" '
     + '        :name="$root.parent.widget_id" src="about:blank" v-once'
     + '        allow="autoplay *; camera *; fullscreen *; payment *"'
     + '        referrerpolicy="origin">'
@@ -907,6 +907,13 @@ Vue.component('pretix-overlay', {
         + shared_lightbox_fragment
         + '</div>'
     ),
+    mounted: function () {
+        if (typeof this.$refs.iframe.addEventListenerBase === "function") {
+            // Workaround for a bug in Cookiebot's magic load event handling (see internal ticket Z#23180085)
+            console.log("pretix Widget is applying circumvention for a bug in Cookiebot's event handling");
+            this.$refs.iframe.addEventListenerBase("load", this.iframeLoaded)
+        }
+    },
     watch: {
         '$root.lightbox': function (newValue, oldValue) {
             if (newValue) {