Add Google Customer Survey code (#9132)

layouts/partials/head.html

@@ -49,3 +49,4 @@ crossorigin="anonymous"></script>
 <script src="{{ "js/custom-jekyll/tags.js" | relURL }}"></script>
 {{ with .Params.js }}{{ range (split . ",") }}<script src="{{ (trim . " ") | relURL }}"></script><!-- custom js added -->
 {{ end }}{{ else }}<!-- no custom js detected -->{{ end }}
+<script async="" defer="" src="//survey.g.doubleclick.net/async_survey?site=6ip6epxiqjqn4qgzemchgtfziy"></script>