removed reference

Author: JustPies

learn-pr/paths/intro-to-azure-application-delivery-services/index.yml

@@ -27,7 +27,6 @@ subjects:
 modules:
 - learn.azure.intro-to-azure-load-balancer
 - learn.azure.intro-to-azure-application-gateway
-- learn.intro-to-azure-front-door
 - introduction-azure-web-application-firewall
 trophy:
   uid: learn.intro-to-azure-application-delivery-services.trophy