[3.11] GH-98543: Fix `asyncio.TaskGroup` to not keep reference to errors after raising ExceptionGroup (GH-98544) (#98550)

GH-98543: Fix `asyncio.TaskGroup`  to not keep reference to errors after raising ExceptionGroup  (GH-98544)
(cherry picked from commit f4a14941e6e54b15012fca067f6a9b2ff29f201a)

Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>