[3.10] bpo-45826: Fix a crash in suggestions.c by checking for `traceback is None` (GH-29590) (GH-29602)

(cherry picked from commit 5d90c467c02ffefdb13c1abc83a171db1a99ffad)

Co-authored-by: Dennis Sweeney <36520290+sweeneyde@users.noreply.github.com>