Squelch ongoing alerts so message is only sent once

token_bot/history_manager/update_trigger.py

@@ -9,6 +9,7 @@ class UpdateTrigger:
     def __init__(self, alert: Alert):
         self._alert : Alert = alert
         self._last_trigger : Tuple[datetime.datetime, int] | None = None
+        self._squelched : bool = False
 
     @property
     def alert(self) -> Alert:
@@ -75,5 +76,9 @@ class UpdateTrigger:
 
             if comparison_operator(new_datum[1], self._last_trigger[1]):
                 self._last_trigger = new_datum
-                return True
+                was_squelched = self._squelched
+                self._squelched = True
+                return not was_squelched # Returns True if squelched otherwise True
+            elif self._squelched:
+                self._squelched = False
         return False