flows: fix error clearing flow background when no files have been uploaded

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

authentik/core/templates/if/end_session.html

@@ -3,16 +3,6 @@
 {% load static %}
 {% load i18n %}
 
-{% block head %}
-{{ block.super }}
-<style>
-.pf-c-background-image::before {
-    background-image: url("{% static 'dist/assets/images/flow_background.jpg' %}");
-    background-position: center;
-}
-</style>
-{% endblock %}
-
 {% block title %}
 {% trans 'End session' %} - {{ tenant.branding_title }}
 {% endblock %}

authentik/flows/api/flows.py

@@ -303,8 +303,12 @@ class FlowViewSet(UsedByMixin, ModelViewSet):
         background = request.FILES.get("file", None)
         clear = request.data.get("clear", False)
         if clear:
-            # .delete() saves the model by default
-            flow.background.delete()
+            if flow.background_url.startswith("/media"):
+                # .delete() saves the model by default
+                flow.background.delete()
+            else:
+                flow.background = None
+                flow.save()
             return Response({})
         if background:
             flow.background = background