[php-src] Issue #10434: Case insensitive str_contains

Issue: https://github.com/php/php-src/issues/10434 Author: tgeene ### Description When str_contains was added to PHP8 I found that it was a useful solution, but the longer time goes on I find that it is lacking. At the moment if I want to check if a string is withing another string and I want it to be case insensitive I must do one of the following: str_contains(strtolower($haystack), $neddle) OR stripos($haystack, $neddle) !== false. I would like to recommend an optional parameter be added to the function str_contains that would allow us to toggle case sensitivity.