When the user's alert count is non-zero, the alert-popup is forced to fetch unread alerts first, and if no unread alerts are discovered this indicates the user's alert count is out-of-sync and needs to be reset.
Add explain text to the "Use custom" value for "Alerting Preferences" per-user option
Add "[Alert Improvements] Can customize advanced alert preferences" permission to control is a user can change the following per-user preferences: "Alerts page options"/"Alert pop-up options"/"Alerts summarize threshold"
Permission granted to Registered user group by default
