Fix Exception when scheduled mail has no subevent

src/pretix/plugins/sendmail/templates/pretixplugins/sendmail/rule_inspect.html

@@ -44,10 +44,14 @@
                     </td>
                     {% if request.event.has_subevents %}
                         <td>
-                            <a href="{% url "control:event.subevent" organizer=request.event.organizer.slug event=request.event.slug subevent=sm.subevent.id %}?returnto={{ request.GET.urlencode|urlencode }}">
-                                {{ sm.subevent.name }}
-                            </a><br>
-                            {{ sm.subevent.get_date_range_display }}
+                            {% if sm.subevent %}
+                                <a href="{% url "control:event.subevent" organizer=request.event.organizer.slug event=request.event.slug subevent=sm.subevent.id %}?returnto={{ request.GET.urlencode|urlencode }}">
+                                    {{ sm.subevent.name }}
+                                </a><br>
+                                {{ sm.subevent.get_date_range_display }}
+                            {% else %}
+                                -
+                            {% endif %}
                         </td>
                     {% endif %}
                     <td>

src/pretix/presale/views/event.py

@@ -511,7 +511,6 @@ class EventIndex(EventViewMixin, EventListMixin, CartMixin, TemplateView):
                 'require_cookie': 'true',
                 'cart_id': request.GET.get('take_cart_id'),
                 **({"locale": request.GET.get('locale')} if request.GET.get('locale') else {}),
-                **({"widget_data": request.GET.get('widget_data')} if request.GET.get('widget_data') else {}),
                 **utm_params,
             }))
         elif request.GET.get('iframe', '') == '1' and len(self.request.GET.get('widget_data', '{}')) > 3:
@@ -527,7 +526,6 @@ class EventIndex(EventViewMixin, EventListMixin, CartMixin, TemplateView):
                     "src": "widget",
                     **({"locale": request.GET.get('locale')} if request.GET.get('locale') else {}),
                     **({"take_cart_id": request.GET.get('cart_id')} if request.GET.get('cart_id') else {}),
-                    **({"widget_data": request.GET.get('widget_data')} if request.GET.get('widget_data') else {}),
                     **utm_params,
                 })
             })