Broken link fixed

Author: pritamso

articles/azure-monitor/index.yml

@@ -116,6 +116,6 @@ landingContent:
           - text: Application Insights
             url: /rest/api/application-insights/  
           - text: Application Insights REST API sandbox
-            url: https://dev.applicationinsights.io
+            url: /rest/api/application-insights/
           - text: Azure Alerts Management SDK for Python
             url: /python/api/azure-mgmt-monitor/azure.mgmt.monitor.monitormanagementclient