Remove file from TOC and index

Author: maud-lv

articles/azure-app-configuration/TOC.yml

@@ -130,8 +130,6 @@
     items:
     - name: Use feature flags
       items:
-      - name: ASP.NET Core
-        href: use-feature-flags-dotnet-core.md
       - name: Spring Boot
         href: use-feature-flags-spring-boot.md
     - name: Enable conditional features with feature filters

articles/azure-app-configuration/index.yml

@@ -152,8 +152,6 @@ landingContent:
           url: quickstart-feature-flag-javascript.md
       - linkListType: tutorial
         links: 
-        - text: Use feature flags in ASP.NET Core
-          url: use-feature-flags-dotnet-core.md
         - text: Use feature flags in Spring Boot
           url: use-feature-flags-spring-boot.md
         - text: Enable conditional features with feature filters