Properly handle MySQL error code 4031 from PHP 8.4

It has been introduced in:
mysql/mysql-server@14508bb

And PHP 8.4 will support it:
php/php-src#13618

src/Driver/API/MySQL/ExceptionConverter.php

@@ -78,6 +78,7 @@ public function convert(Exception $exception, ?Query $query): DriverException
             2002,
             2005,
             2054 => new ConnectionException($exception, $query),
+            4031,
             2006 => new ConnectionLost($exception, $query),
             1048,
             1121,