Fix screenshots with scaling or size argument

[bruyeret]

The screenshot feature did not work with several renderwindows linked to a root render window.

To reproduce the issue, you can edit the ManyRenderWindows example.
Change the action of the Remove render window button to make screenshots.
To do so, at the line button.addEventListener, replace the listener using this code:

  button.addEventListener('click', () => {
    renderWindowView.captureNextImage(null, { scale: 5 }).then((result) => {
      const newWindow = window.open('');
      newWindow.document.write(`<img src="${result}" alt="Image Preview" />`);
    });
    renderWindow.render();
  });

[finetjul]

LGTM

[sankhesh]

👍

[finetjul]

LGTM