[3.10] gh-103848: Adds checks to ensure that bracketed hosts found by urlsplit are of IPv6 or IPvFuture format (#103849) (#126975)

Co-authored-by: Gregory P. Smith <greg@krypto.org>
(cherry picked from commit 29f348e232e82938ba2165843c448c2b291504c5)

Co-authored-by: JohnJamesUtley <81572567+JohnJamesUtley@users.noreply.github.com>