Refs #23919 -- Removed most of remaining six usage

Thanks Tim Graham for the review.

tests/test_client/views.py

@@ -1,3 +1,4 @@
+from urllib.parse import urlencode
 from xml.dom.minidom import parseString
 
 from django.contrib.auth.decorators import login_required, permission_required
@@ -13,7 +14,6 @@ from django.shortcuts import render
 from django.template import Context, Template
 from django.test import Client
 from django.utils.decorators import method_decorator
-from django.utils.six.moves.urllib.parse import urlencode
 
 
 def get_view(request):