Remove extraneous doc from this PR

Author: jonburchel

articles/ai-foundry/concepts/disable-preview-features-with-rbac.md

@@ -5,8 +5,6 @@ items:
     href: ../../concepts/authentication-options-ai-foundry.md
   - name: Role-based access control
     href: ../../concepts/rbac-azure-ai-foundry.md
-  - name: Disable preview features with RBAC
-    href: ../../concepts/disable-preview-features-with-rbac.md
   - name: Rotate API access keys
     href: ../../../ai-services/rotate-keys.md?context=/azure/ai-foundry/context/context
   - name: Configure key-less authentication