fix(TimerMgr): add warning for rescheduling non-existent timers

utils/TimerMgr.js

@@ -66,6 +66,10 @@ class TimerMgr {
     }
 
     reschedule(id, timeout) {
+        if (!this.hasTimer(id)) {
+            log.warn(`Cannot reschedule non-existent timer with id ${id}`);
+            return false;
+        }
         this.#timers[id].reschedule(timeout);
     }
 }