I would suggest a better alternative would be to you use free icon library called Font Awesome. You should be able to find a similar icon that you need there. There should be some documentation on how to set up the CDN on their website.

Furthermore, just as a recommendation. You shouldn’t need do_shortcode, there’s no shortcode in your string. a regular echo statement should suffice. This may, actually, fix your problem if do_shortcode() is escaping some characters.