Browser scrolls to content preview on page load

This occurs wherever the Content Preview UI element is used. There may be instances where this is the preferred behavior, but I think there are also cases where you wouldn't want the browser to automatically scroll to the embedded file.

## Steps to Reproduce:
1. Visit the [Content Preview Documentation](https://developer.box.com/guides/embed/ui-elements/preview/)
2. Wait a couple seconds
3. Notice how instead of starting at the top of the page, the browser scrolls to the content preview demo.

Start with the Content Preview Documentation reproduction and identify the Content Preview UI entry point responsible for the page-load scroll. Confirm the behavior across pages that embed the preview, then ensure the documentation page remains at the top on load without breaking cases where scrolling is intentional.

Written by the indexing model from the issue text.