[php-src] PR #25191: Fix GH-25189: parse_ini_string() ignores everything after a NUL byte

Pull Request: https://github.com/php/php-src/pull/25191 Author: iliaal parse_ini_string() stopped at the first NUL byte because zend_ini_prepare_string_for_scanning() took the scanner limit from strlen(), while parse_ini_file() scans the same bytes in full. Pass the length through zend_parse_ini_string() instead; the -d entries and FPM callers pass strlen() and behave as before. Targeting master since the signature changes and a string with a NUL byte can now fail to parse where it used to return a truncated result. Fixes GH-25189