Hi Rishi,
I have checked and you can use the hook : fre_after_social_links to adding new social link via child-theme:
Ex: add this code into child-theme/functions.php file to add Linkedin link into the social link
function cs_add_linkedin_link(){
echo '<li class="fre-gp-link"><a target="_blank" rel="noopener noreferrer" href="https://www.linkedin.com/abc/"><span><i class="fa fa-linkedin"></i></span>Linkedin</a></li>' ;
}
add_action('fre_after_social_links','cs_add_linkedin_link');
Hope this helps!
Dan.