Do not notify again for old events

Resending the notification here can trigger other system components or
apps that listen to new notifications, such as connected smart watches
or automation tools.

Fixes https://github.com/vector-im/element-android/issues/1673

changelog.d/1673.bugfix

@@ -0,0 +1 @@
+Avoid resending notifications that are already shown

vector/src/main/java/im/vector/app/features/notifications/NotificationDrawerManager.kt

@@ -457,7 +457,7 @@ class NotificationDrawerManager @Inject constructor(private val context: Context
 
             if (eventList.isEmpty() || eventList.all { it.isRedacted }) {
                 notificationUtils.cancelNotificationMessage(null, SUMMARY_NOTIFICATION_ID)
-            } else {
+            } else if (hasNewEvent) {
                 // FIXME roomIdToEventMap.size is not correct, this is the number of rooms
                 val nbEvents = roomIdToEventMap.size + simpleEvents.size
                 val sumTitle = stringProvider.getQuantityString(R.plurals.notification_compat_summary_title, nbEvents, nbEvents)