Fix typo in test_dataclasses.py (gh-95735) (gh-95740)

`dataclass` was called as a function when it was almost certainly intended to be a decorator.
(cherry picked from commit 59e09efe888affe549e9249f188797c1325edecc)

Co-authored-by: da-woods <dw-git@d-woods.co.uk>

Co-authored-by: da-woods <dw-git@d-woods.co.uk>
1 file changed