[3.10] gh-115197: Stop resolving host in urllib.request proxy bypass (GH-115210)...

[3.10] gh-115197: Stop resolving host in urllib.request proxy bypass (GH-115210) (GH-116070)

Use of a proxy is intended to defer DNS for the hosts to the proxy itself, rather than a potential for information leak of the host doing DNS resolution itself for any reason.  Proxy bypass lists are strictly name based.  Most implementations of proxy support agree.
(cherry picked from commit c43b26d02eaa103756c250e8d36829d388c5f3be)

Co-authored-by: Weii Wang <weii.wang@canonical.com>