Change exercise level to 400

Updated the level of the exercise from 300 to 400.

Author: staleycyn

Instructions/Exercises/M05-Unit 6 Create a front door for a highly available web application using the Azure portal.md

@@ -4,12 +4,11 @@ Exercise:
   module: Module 05 - Load balancing HTTP(S) traffic in Azure
   description: Create and configure Azure Front Door.
   duration: 30 minutes
-  level: 300
+  level: 400
   islab: true
   primarytopics:
     - Azure
     - Azure Front Door
-    - Azure Portal
 ---
 
 # M05-Unit 6 Create a Front Door for a highly available web application using the Azure portal