feature: Add an option to enable Telegram to work behind a proxy. (#6125)

Co-authored-by: Frank Elsinga <frank@elsinga.de>

server/notification-providers/line.js

@@ -19,6 +19,7 @@ class Line extends NotificationProvider {
                     "Authorization": "Bearer " + notification.lineChannelAccessToken
                 }
             };
+            config = this.getAxiosConfigWithProxy(config);
             if (heartbeatJSON == null) {
                 let testMessage = {
                     "to": notification.lineUserID,