To completely remove emojis this is the code:
remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
remove_action( 'wp_print_styles', 'print_emoji_styles' );
remove_action( 'admin_print_styles', 'print_emoji_styles' );
So to check if any of those are active you could use has_action() like this:
$emoji_script front = has_action( 'wp_head', 'print_emoji_detection_script' );
if( $emoji_script_front ) {
// The emoji script is loaded on the front end
}
You could do different things for each of the actions. has_action does not care about priority, and this should work in the functions.php file since it runs later than all of those actions.