api: remove unused function (#28962)

src/authentic2/api_views.py

@@ -305,11 +305,6 @@ def user(request):
     return request.user.to_json()
 
 
-def attributes_hash(attributes):
-    attributes = sorted(attributes, key=lambda at: at.name)
-    return hash(tuple((at.name, at.required) for at in attributes))
-
-
 class BaseUserSerializer(serializers.ModelSerializer):
     ou = serializers.SlugRelatedField(
         queryset=get_ou_model().objects.all(),