Fix deprecation of implicitly marking parameter as nullable in PHP 8.4

[JanJakes]

Fixes the following errors from Playground Compatibility Reports:

WP_SQLite_Driver::recreate_table_from_information_schema(): Implicitly marking parameter $column_map as nullable is deprecated, the explicit nullable type must be used instead in /internal/shared/sqlite-database-integration/wp-includes/sqlite-ast/class-wp-sqlite-driver.php on line 2783

WP_SQLite_Driver::set_result_from_affected_rows(): Implicitly marking parameter $override as nullable is deprecated, the explicit nullable type must be used instead in /internal/shared/sqlite-database-integration/wp-includes/sqlite-ast/class-wp-sqlite-driver.php on line 3541

WP_SQLite_Driver::new_driver_exception(): Implicitly marking parameter $previous as nullable is deprecated, the explicit nullable type must be used instead in /internal/shared/sqlite-database-integration/wp-includes/sqlite-ast/class-wp-sqlite-driver.php on line 3564

WP_SQLite_Driver_Exception::__construct(): Implicitly marking parameter $previous as nullable is deprecated, the explicit nullable type must be used instead in /internal/shared/sqlite-database-integration/wp-includes/sqlite-ast/class-wp-sqlite-driver-exception.php on line 19