bpo-32896: Fix error when subclassing a dataclass with a field that uses a default_factory (GH-6170) (GH-6171)

Fix the way that new annotations in a class are detected.
(cherry picked from commit 8f6eccdc64cab735c47620fea948e64b19f83684)

Co-authored-by: Eric V. Smith <ericvsmith@users.noreply.github.com>
3 files changed