[GIT-PULLS] [php-src] PR #22974: SAPI: clear current_user and content_type_dup after releasing them

Pull Request: https://github.com/php/php-src/pull/22974
Author: iliaal

`sapi_deactivate_module()` frees `current_user` and `content_type_dup` but leaves both pointers set, unlike `auth_user`, `auth_password` and `auth_digest` right above them. Nothing reads either field between the free and the next `sapi_activate()`, so this is consistency rather than a live bug, and a second deactivate would double-free.

This is older than the zend_string conversion in php/php-src#22902, so it targets 8.4.