PHP 8.2 - Deprecated

Hi!

There is another deprecated warning for PHP 8.2

```txt
10-Jan-2025 11:11:30 UTC] PHP Deprecated: preg_match(): Passing null to parameter #2 ($subject) of type string is deprecated in /home/wp/disk/wordpress/wp-content/plugins/webp-express/webp-express.php on line 45
```