[3.8] Update Sphinx bpo role to use redirect URI. (#91892)

* Update Sphinx bpo role to use redirect URI. (GH-32342)

* [3.8] Update Sphinx bpo role to use redirect URI. (GH-32342).
(cherry picked from commit 08cfe079)

Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>