Switch to .NET 8, 9, and 10 transport feeds for tests

Author: lbussell

tests/Microsoft.DotNet.Docker.Tests/TestAppArtifacts/NuGet.config.nightly

@@ -3,8 +3,8 @@
   <packageSources>
     <clear />
     <add key="dotnet-public" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-public/nuget/v3/index.json" />
-    <add key="dotnet8" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8/nuget/v3/index.json" />
-    <add key="dotnet9" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet9/nuget/v3/index.json" />
-    <add key="dotnet10" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-dotnet-0fc3e418/nuget/v3/index.json" />
+    <add key="dotnet8" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8-transport/nuget/v3/index.json" />
+    <add key="dotnet9" 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-transport/nuget/v3/index.json" />
   </packageSources>
 </configuration>