Small issue with custom code for header. Any help is appreciated!

Site URL: https://www.nickdavid.co.uk/

Hi,

I am having an issue with a custom code. This code is supposed to give me the option to add social icons to the top main navigation bar. 

The code works well, but with one issue when making the icons open in a new tab.  When navigating back to the original Site, the clicked icon is marked with a dotted squared. It disappears again when clicking on other parts of the site. But would like to know if there are any way to remove. 

I have attached images for example!

Here is the code that is injected in the header: 

<meta name="google-site-verification" content="MZTF-OSAD1RlW6uiJLGfumxXTi6w2gYs9P-qMLsaoAY" />

<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.2/css/all.css" integrity="sha384-fnmOCqbTlWIlj8LyTjo7mOUStjsKC4pOpQbqyi7RrhN7udi9RwhKkMHpvLbHG9Sr" crossorigin="anonymous">

Here is the code used to make the social icons and make them open in a new tab. This is added directly as the main navigation link. 

<i class="fab fa-linkedin fa-lg"></i>

Thank you for your help!