toc.yml: Create unit tests from Standard workflow definitions with Visual Studio Code

Add article to ToC. You might see a merge conflict after you merge the other unit test article, but you get a chance to fix.

Author: ecfan

articles/logic-apps/toc.yml

@@ -463,6 +463,8 @@ items:
       href: update-workflow-definition-language-schema.md
   - name: Test
     items:
+    - name: Create unit tests from Standard workflow definitions
+      href: create-unit-tests-standard-workflow-definitions-visual-studio-code.md
     - name: Test workflows with mock outputs
       href: test-logic-apps-mock-data-static-results.md
   - name: Deploy