Alerting: Call RLock() before reading sendAlertsTo map (#99812)
* Alerting: Call RLock() before reading sendAlertsTo map
* defer unlocking
* drive-tru fix for another lock
* less time holding the lock in SyncAndApplyConfigFromDatabase
(cherry picked from commit 39f212a965)
Co-authored-by: Santiago <santiagohernandez.1997@gmail.com>