Fix property not callable

scipost/templatetags/user_groups.py

@@ -9,4 +9,4 @@ def is_edcol_admin(user):
     Assign template variable (boolean) to check if user is Editorial Administator.
     This assignment is limited to a certain context block!
     """
-    return user.groups.filter(name='Editorial Administrators').exists() or user.is_superuser()
+    return user.groups.filter(name='Editorial Administrators').exists() or user.is_superuser