Update Nuget.config to include .NET 11 paths (#11119)

* Update Nuget.config to include .NET 11 paths

* Remove .NET 7/8/9 configs

* Revert the previous changes

Author: harshit7962

NuGet.config

@@ -14,6 +14,8 @@
     <add key="dotnet9-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet9-transport/nuget/v3/index.json" />
     <add key="dotnet10" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet10/nuget/v3/index.json" />
     <add key="dotnet10-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet10-transport/nuget/v3/index.json" />
+    <add key="dotnet11" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet11/nuget/v3/index.json" />
+    <add key="dotnet11-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet11-transport/nuget/v3/index.json" />
   </packageSources>
   <auditSources>
     <clear />