http: decodes url.username and url.password for authorization header

This change properly decodes the url.username and url.password for
the authorization header constructed from the URL object for
http(s) requests.

Fixes: https://github.com/nodejs/node/issues/31439

PR-URL: https://github.com/nodejs/node/pull/39310


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: James M Snell <jasnell@gmail.com>