Add az login with tenant instruction

Author: simonkurtz-MSFT

.devcontainer/post-start-setup.sh

@@ -65,7 +65,11 @@ echo "🎉 Your APIM Samples environment is ready to use!"
 echo -e "\n"
 echo " Next Steps:"
 echo ""
-echo "   1. Open a new terminal and log in via the Azure CLI: az login"
+echo "   1. Open a new terminal and log in via the Azure CLI with either command."
+echo "      See TROUBLESHOOTING.md in the root for details."
+echo ""
+echo "        - az login"
+echo "        - az login --tenant <your-tenant-id>"
 echo ""
 echo "   2. Wait until Codespace is fully started (it's fairly quick):"
 echo "        - Watch progress indicators in status bar"