[PHP 8.2] Replace deprecated utf8_encode()

[jofranz]

Warning: This function has been DEPRECATED as of PHP 8.2.0. Relying on this function is highly discouraged.

https://www.php.net/manual/en/function.utf8-encode.php

See: https://wiki.php.net/rfc/remove_utf8_decode_and_utf8_encode

aip/Civi/AIP/Reader/CSV.php:            $new_record[$key] = utf8_encode($value);