Update setup-overview.mdx

Update to add odc link

Author: clairekinde11

src/content/docs/billing/get-started/setup-overview.mdx

@@ -23,7 +23,7 @@ Billing is big step for a business, so it’s a good idea to review the process
 6. Enable subscription self-serve (optional)
     1. [Create a plan selector](/billing/billing-user-experience/plan-selection/)
     2. [Enable self-serve portal](/build/set-up-options/self-serve-portal-for-orgs/)
-7. Update your code
+7. [Update your code and registration URLs](/billing/billing-user-experience/add-billing-to-url-sdk/)
 8. Test the setup and get your first subscriber!
 
 ## ⚠️ Test in a non-production environment