Recovery (all-clear) notifications were being silently suppressed during
quiet hours for any non-critical alert. Since powered-off alerts default
to Warning level, users who received an alert at 2pm would never get the
recovery notification if the VM came back during quiet hours.
Quiet hours are intended to suppress noisy firing alerts, not to hide
the fact that an issue has resolved. If you got the alert, you should
always get the all-clear.
Remove the ShouldSuppressResolvedNotification gate from handleAlertResolved.
The notifyOnResolve toggle (explicit user preference) is still respected.
Fixes#1259