Revert nuget.config to original Microsoft feed

Co-authored-by: gfs <98900+gfs@users.noreply.github.com>

Author: Copilot

nuget.config

@@ -2,6 +2,6 @@
 <configuration>
   <packageSources>
     <clear />
-    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
+    <add key="PublicRegistriesFeed" value="https://pkgs.dev.azure.com/microsoft-sdl/General/_packaging/PublicRegistriesFeed/nuget/v3/index.json" />
   </packageSources>
 </configuration>