http2: add support for sensitive headers

Add support for “sensitive”/“never-indexed” HTTP2 headers.

Fixes: https://github.com/nodejs/node/issues/34091

PR-URL: https://github.com/nodejs/node/pull/34145


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>