[hf] decrease healthcheck interval to 10 min
rationale:
- with spike in channels, we are seeing more failures
- since our focus is mostly on signalc, we are paying particularly close attention to channel health
- if we have a shorter interval, we will recover more quickly from actual failures (20 min max downtime) while we are not around to handhold the system
- at the same time, 10 min is not short enough that we risk alert fatigue from a potential bump in false positives