Add userfront to disallowed paths in robots.txt (#4097)

Author: SeanBobby

astro/public/robots.txt

@@ -38,5 +38,6 @@ Disallow: /lp/firebase
 Disallow: /lp/oauth
 Disallow: /lp/google-cloud
 Disallow: /lp/aws
+Disallow: /lp/userfront
 Disallow: /lp/fusionauth-meeting-accelerator
 Sitemap: https://fusionauth.io/sitemap-all.xml