Using specific PDO drivers instead of PDOConnection on PHP 8.4+

To ensure compatibility with PHP 8.4 and PHP 8.5, this change updates the database connection classes to use the new driver-specific PDO connection classes (Pdo\Mysql, Pdo\Pgsql, Pdo\Sqlite) that were introduced in PHP 8.4. This avoids deprecation warnings that would otherwise appear starting in PHP 8.5.

The changes primarily involve conditionally using the new PDO driver classes when the PHP version is 8.4 or higher. This affects the mysql, pgsql, and sqlite database drivers. For the SQLite driver, the code has also been updated to use the new createFunction() syntax with first-class callable syntax when running on PHP 8.4+