DE classad monitoring advertise issue

[StevenCTimm]

It was found in Frontend testing that various things in the Frontend monitoring are tied to a string that includes the credential ID. In the case of entries that run only with scitokens and not with proxies, this credential ID is null and thus some of the graphs do not get filled. See glideinwms issue tracker for what was done there. Evidently this is one of the places where the DE and FE code have diverged and have to be fixed separately.