add custom sidebar link to copilot/tutorials (#58194)

Author: rsese

content/copilot/tutorials/index.md

@@ -32,6 +32,9 @@ redirect_from:
 contentType: tutorials
 heroImage: /assets/images/banner-images/hero-3.png
 layout: bespoke-landing
+sidebarLink:
+ text: All tutorials
+ href: /copilot/tutorials
 recommended:
  - /copilot/tutorials/copilot-chat-cookbook
  - /copilot/tutorials/customization-library