[php-src] Issue #10891: dba_insert() for ini files can result in duplicate keys

Issue: https://github.com/php/php-src/issues/10891 Author: nielsdos ### Description The following code: ```php <?php @unlink("test.ini"); touch("test.ini"); $db = dba_open("test.ini", "wl", "inifile"); var_dump($db); var_dump(dba_fetch("nonexisting", $db)); var_dump(dba_insert("nonexisting", "newvalue", $db)); var_dump(dba_insert("nonexisting", "newvalue", $db)); dba_close($db); ``` Resulted in this output: ``` resource(7) of type (dba) bool(false) bool(true) bool(true) ``` But I expected this output instead: ``` resource(7) of type (dba) bool(false) bool(true) bool(false) ``` And additionally: not an extra same-key entry in my ini file. Because according to the docs at https://www.php.net/manual/en/function.dba-insert.php: > If this key already exist in the database, this function will fail. ### PHP Version PHP 8.1+ ### Operating System Linux 6.2.x