remove the WebSocket listeners

Author: odeimaiz

services/static-webserver/client/source/class/osparc/study/Conversations.js

@@ -41,6 +41,9 @@ qx.Class.define("osparc.study.Conversations", {
       const viewWidth = 600;
       const viewHeight = 700;
       const win = osparc.ui.window.Window.popUpInWindow(conversations, title, viewWidth, viewHeight);
+      win.addListener("close", () => {
+        conversations.dispose(); // this will remove the WebSocket listeners
+      }, this);
       return win;
     },