Unregister all observers if all reconnection attempts failed

app/src/main/java/chat/rocket/android/service/RocketChatWebSocketThread.java

@@ -315,10 +315,11 @@ public class RocketChatWebSocketThread extends HandlerThread {
                     }
                     reconnectSubscription.clear();
                   },
-                            err -> {
-                              logErrorAndUnsubscribe(reconnectSubscription, err);
+                  error -> {
+                    logErrorAndUnsubscribe(reconnectSubscription, error);
                     connectivityManager.notifyConnectionLost(hostname,
                             ConnectivityManagerInternal.REASON_NETWORK_ERROR);
+                    new Handler(getLooper()).post(this::unregisterListeners);
                   }
             )
     );