Log failed health checks from the HealthEndpoint

[ezraroi]

It will be great to log to the logger all failed health checks every time the health endpoint is being called.
In our system, we get alerts on unhealthy services, but if we don't check the health endpoint immediately, it is impossible to know the reason.

[snicoll]

@ezraroi there is a WARN log for every indicator since 1.5.4.RELEASE (#9110), we have no intention to raise that to ERROR.