Ensure certificate(s) used to sign .NET archives and release manifests is onboarded w/MicroBuild #16240
Description
The certificate(s) used to sign .NET archives and release manifests must be onboarded w/MicroBuild. Once the certificate(s) are decided and specified in https://github.com/dotnet/release/issues/1077, we need to talk to MicroBuild to ensure they are onboarded.