feat(notifications) trigger iframe api event when a notification occurs (#12952)

* feat(notifications) trigger iframe api event when a notification occurs

* remove useless comment

* fix typo

modules/API/API.js

         });
     }
 
+    /**
+     * Notify the external app that a notification has been triggered.
+     *
+     * @param {string} title - The notification title.
+     * @param {string} description - The notification description.
+     *
+     * @returns {void}
+     */
+    notifyNotificationTriggered(title: string, description: string) {
+        this._sendEvent({
+            description,
+            name: 'notification-triggered',
+            title
+        });
+    }
+
     /**
      * Notify external application that the video quality setting has changed.
      *

modules/API/external/external_api.js

     'mouse-enter': 'mouseEnter',
     'mouse-leave': 'mouseLeave',
     'mouse-move': 'mouseMove',
+    'notification-triggered': 'notificationTriggered',
     'outgoing-message': 'outgoingMessage',
     'participant-joined': 'participantJoined',
     'participant-kicked-out': 'participantKickedOut',

react/features/notifications/actions.ts

         const { disabledNotifications = [], notifications, notificationTimeouts } = getState()['features/base/config'];
         const enabledFlag = getFeatureFlag(getState(), NOTIFICATIONS_ENABLED, true);
 
+        const { descriptionKey, titleKey } = props;
+
         const shouldDisplay = enabledFlag
-            && !(disabledNotifications.includes(props.descriptionKey ?? '')
-                || disabledNotifications.includes(props.titleKey ?? ''))
+            && !(disabledNotifications.includes(descriptionKey ?? '')
+                || disabledNotifications.includes(titleKey ?? ''))
             && (!notifications
-                || notifications.includes(props.descriptionKey ?? '')
-                || notifications.includes(props.titleKey ?? ''));
+                || notifications.includes(descriptionKey ?? '')
+                || notifications.includes(titleKey ?? ''));
+
+        if (typeof APP !== 'undefined') {
+            APP.API.notifyNotificationTriggered(titleKey, descriptionKey);
+        }
 
         if (shouldDisplay) {
             return dispatch({