Restore nuget.config to defaults

Author: Arlodotexe

nuget.config

@@ -1,7 +1,7 @@
 <configuration>
   <packageSources>
+    <clear />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
-    <add key="PullRequests" value="https://pkgs.dev.azure.com/dotnet/CommunityToolkit/_packaging/CommunityToolkit-PullRequests/nuget/v3/index.json" protocolVersion="3" />
     <add key="MainLatest" value="https://pkgs.dev.azure.com/dotnet/CommunityToolkit/_packaging/CommunityToolkit-MainLatest/nuget/v3/index.json" protocolVersion="3" />
   </packageSources>
   <disabledPackageSources>