[3.13] gh-123213: Fixed xml.etree.ElementTree.Element.extend and assignment to no longer hide exceptions (GH-123214) (#123257)

gh-123213: Fixed xml.etree.ElementTree.Element.extend and assignment to no longer hide exceptions (GH-123214)
(cherry picked from commit 90b6d0e0f8f07d7443695e14a18488cb499d3b4d)

Co-authored-by: Bar Harel <bharel@barharel.com>