[QST] How how to expose __dict__ when `cudf.pandas` is enabled?

Some of the pandas tests spelunk the `__dict__` of a module to determine what to collect. E.g. `tests/dtypes/test_generic.py` does:
```
from pandas.core.dtypes import generic as gt
...
@pytest.mark.parametrize("abctype", [e for e in gt.__dict__ if e.startswith("ABC")])
def test_abc_coverage(self, abctype):
```

with `cudf.pandas` enabled:
```
from pandas.core.dtypes import generic as gt
gt.__dict__.keys() # does _not_ contain ABCCategorical
```