Remove link from mentioned username in comment

@astghik Thanks for the note. We actually spent some time last night coding and came up with an even better workaround. 

The problem with the aforementioned JavaScript override is that it still puts the href link in the HTML source, and since the JavaScript doesn't hide it from Google we were still were getting dinged for broken links to these non-existent author pages.

To solve this, we created a custom function in our custom plugin that hooks into the Wordpress the_author_link() function and clears it from there.

Works perfectly, and completely eliminates this mess for us. You might need to modify this based upon your custom plugin's functionality as it relates to authors, but edit_posts was a perfect "litmus test" for us here.

function our_custom_author_link( $link, $author_id, $author_nicename ) {

    if ( !user_can( $author_id, 'edit_posts' ) ) {
        return '';
    }
    // Otherwise, return $link unmodified
    return $link;
}
add_filter( 'author_link', 'our_custom_author_link', 10 , 3 );