centralwidget.cpp: update to KF6Notifications

Author: huantianad

src/centralwidget.cpp

@@ -50,8 +50,9 @@ void CentralWidget::setupWebView() {
             notification->setText(notificationInfo->message());
             notification->setPixmap(
                 QPixmap::fromImage(notificationInfo->icon()));
-            notification->setDefaultAction("View");
-            connect(notification, &KNotification::defaultActivated,
+            KNotificationAction* defaultActivated = 
+                notification->addDefaultAction("View");
+            connect(notification, &defaultActivated,
                     [&, notificationInfo = std::move(notificationInfo)]() {
                       notificationInfo->click();
                       show();