Fix default value of one of HTT flags
It is a followup of MR: !58327 (merged) One of the flags default value was left None which is not supported by the new flags system. Actually unclear why. Also added unit test. Tagging @fwinkl @ksuch
It is a followup of MR: !58327 (merged) One of the flags default value was left None which is not supported by the new flags system. Actually unclear why. Also added unit test. Tagging @fwinkl @ksuch