title: How to add background image in LoginOverlay in vaadin 13?
body: <p>I am using Vaadin 13s' new component LoginOverlay. I want to add background image using setTitle() as shown here.</p>
  
  <pre><code>        loginOverlay = new LoginOverlay();
          loginOverlay.setOpened(true);
          Component titleComponent = new Image();
          ((Image) titleComponent).setSrc("frontend/img/seven-oceans.jpg");
          loginOverlay.setTitle(titleComponent);
          loginOverlay.setDescription("Insert Employee Id and Password");
          loginOverlay.setAction("login");
          loginOverlay.addForgotPasswordListener(e-&gt;{
              Notification.show("Forgot password not yet handled", 30, Notification.Position.TOP_CENTER);
          });
          add(loginOverlay);
  </code></pre>
  
  <p>But, no image is loading.</p>