[3.12] Revert "GH-96145: Add AttrDict to JSON module for use with object_hook (GH-96146)" (GH-105948) (#106117)

Revert "GH-96145: Add AttrDict to JSON module for use with object_hook (GH-96146)" (GH-105948)

This reverts commit 1f0eafa844bf5a380603d55e8d4b42d8c2a3439d.
(cherry picked from commit d3af83b9342457d8b24476baeb799f7506ff04f3)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>