Added test action common schema definition

Author: ishasahni1

articles/azure-monitor/toc.yml

@@ -586,6 +586,8 @@ items:
         href: alerts/alerts-common-schema.md
       - name: Common alert schema definition
         href: alerts/alerts-common-schema-definitions.md
+      - name: Common alert schema definition for Test action group
+        href: alerts/alerts-common-schema-test-action-definitions.md       
       - name: Integrate the common alert schema with Logic Apps
         href: alerts/alerts-common-schema-integrations.md
       - name: SMS alert behavior
@@ -1556,4 +1558,4 @@ items:
   - name: Pricing calculator
     href: https://azure.microsoft.com/pricing/calculator/
   - name: Regional availability
-    href: https://azure.microsoft.com/global-infrastructure/services/?regions=all&products=monitor
+    href: https://azure.microsoft.com/global-infrastructure/services/?regions=all&products=monitor