Tags inside of <a> tags on lightbox component to be clickable

The current way of checking click outside of the lightbox content to close it causes a problem if there is, for example, `<span>` tag inside of `<a>` tag.

```html
<a href="http://www.sky.com">Sky</a> <!-- works -->
<a href="http://www.sky.com">Go to <span>Sky</span></a> <!-- doesn't work if "Sky" is clicked -->
```

This fix checks if the click event target itself or any of its parent is `<a>` tag instead of just checking the event target itself.