[GIT-PULLS] [php-src] PR #22691: ext/curl: Deprecate the NTLM_WB constants

Pull Request: https://github.com/php/php-src/pull/22691
Author: GrahamCampbell

libcurl removed NTLM_WB support in 8.8.0, so on any current libcurl the `CURLAUTH_NTLM_WB` bit is silently filtered out of `CURLOPT_HTTPAUTH`/`CURLOPT_PROXYAUTH` masks and the `CURL_VERSION_NTLM_WB` feature bit is never set; only builds against libcurl older than 8.8.0 can still use the feature at all.

This deprecates both constants with `#[\Deprecated]`, following the `CURLOPT_BINARYTRANSFER` precedent from PHP 8.4, so code still referencing NTLM_WB is nudged to drop it. The `NTLMWB` key in `curl_version()['feature_list']` is kept and continues to report `false` at runtime. This is also a first step in preparing for curl's scheduled removal of NTLM support altogether in September 2026 (https://curl.se/dev/deprecate.html); the still-functional `CURLAUTH_NTLM` and `CURL_VERSION_NTLM` constants are intentionally left alone.