Make the PIP Jitsi look and feel like the 1:1 PIP

* Similar sizing
* Fix pointers so the jitsi widget doesn't feel clickable when it's not
  * We might want to introduce click-to-visit-room for the Jitsi widget (like the 1:1 call), however the Jitsi widget has many more controls to worry about
* Remove the menu bar from the widget to avoid accidents

src/components/views/elements/PersistentApp.js

@@ -82,6 +82,7 @@ export default class PersistentApp extends React.Component {
                     showDelete={false}
                     showMinimise={false}
                     miniMode={true}
+                    showMenubar={false}
                 />;
             }
         }