* Report prolonged report status failures
The agent report transient failures, but this is not very indicative of
customer failures. The transient failures generally resolve themselves, so the
transients are not very useful for a dashboard. This change tracks failures
that repeat for 15 minutes, and then report them. If an operation fails and
succeeds within 15 minutes, the timer resets. It must be a continual stream of
errors for 15 minutes for this telemetry event to trigger.
* default ErrorState's min_timedelta to a const
