Shrink mypy whitelist for `tests.test_transforms.test_transforms_post_transforms` (#14141)

Co-authored-by: daniel.eades <daniel.eades@seebyte.com>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

pyproject.toml

@@ -251,8 +251,6 @@ module = [
     "tests.test_extensions.test_ext_inheritance_diagram",
     # tests/test_intl
     "tests.test_intl.test_intl",
-    # tests/test_transforms
-    "tests.test_transforms.test_transforms_post_transforms",
     # tests/test_util
     "tests.test_util.test_util_i18n",
     "tests.test_util.test_util_inspect",