[9.x] PHP8 string functions for Str class (#38011)
[9.x] PHP8 string functions for Str class (#38011)

* use str_contains over mb_strpos

* use str_ends_with over substr

* use str_starts_with over strncmp
crynobone/framework,lucasmichot/framework,dwightwatson/framework,mul14/laravel-framework,hafezdivandari/framework,morrislaptop/framework,samlev/framework,morrislaptop/framework,driesvints/framework,dwightwatson/framework,arturock/framework,mul14/laravel-framework,mul14/laravel-framework,leo108/laravel_framework,hafezdivandari/framework,crynobone/framework,driesvints/framework,arturock/framework,laravel/framework,notebowl/laravel-framework,JamesForks/framework,lucasmichot/framework,mul14/laravel-framework,notebowl/laravel-framework,samlev/framework,arturock/framework,laravel/framework,leo108/laravel_framework,JamesForks/framework