fix lector related group view

lectures/views.py

@@ -374,6 +374,13 @@ def view_lector(request, id):
             # just because of the related_lecture_id being wrong.
             related_lecture_id = None
 
+    related_group_id = get_related_group_id(request)
+    group = (
+        LectureGroup.objects.get(id=related_group_id)
+        if related_group_id is not None
+        else None
+    )
+
     return render(
         request,
         "lectures/view_lector.html",
@@ -384,7 +391,8 @@ def view_lector(request, id):
             "header_name": lector.name,
             "header_desc": "Lektor",
             "related_lecture_id": related_lecture_id,
-            "related_group_id": get_related_group_id(request),
+            "related_group_id": related_group_id,
+            "group": group,
             "lector": lector,
             "lectures": lectures,
         },