Update TOC.yml (MicrosoftDocs#4160)

Author: dbradish-microsoft

docs-ref-conceptual/TOC.yml

@@ -170,7 +170,6 @@
       href: azure-cli-extension-alias.md
 - name: Tutorials
   items:
-  - name: Work with service principals
   - name: Learn to use the Azure CLI
     items:
       - name: 1 - Welcome to the Azure CLI!