fix critical conflict with oxigen builder

hi on frontier-restrict-media.php file i add a line that fix critical conflict with oxygen Builder

replace

//Check if it is an admin query
	if ($query->is_admin && !current_user_can( 'edit_others_posts' ))
		{
		//Check if it is an attachment query
		if ($query->query['post_type'] === 'attachment')
			{
			// Get current user, and author=current user to query
			$current_user = wp_get_current_user();
			$query->set('author', $current_user->ID);
			}
		}
	return $query;

with this

//Check if it is an admin query
    if(!function_exists('wp_get_current_user')) { include(ABSPATH . "wp-includes/pluggable.php"); } // ALNUX ADD LINE
	if ($query->is_admin && !current_user_can( 'edit_others_posts' ))
		{
		//Check if it is an attachment query
		if ($query->query['post_type'] === 'attachment')
			{
			// Get current user, and author=current user to query
			$current_user = wp_get_current_user();
			$query->set('author', $current_user->ID);
			}
		}
	return $query;

this will fix critical error