HiveServer2: Preauthenticated subject for http transport is not retained for entire duration of http communication in some cases

As implemented in HIVE-8705, for http transport, we add the logged in subject's credentials in the http header via a request interceptor. The request interceptor doesn't seem to be getting used for some http traffic (e.g. knox ssl in the same rpc). It would also be better to cache the logged in subject for the duration of the whole session.