[BUG] find_common_type rasies TypeError with ListDtype

[oliverholworthy]

Describe the bug

Related to #12083 , which has issues with this find_common_type function.

I'm creating this new issue, since the issue with the function is not limited to concatenation (frame.values also results in errors with list columns). Fixing this issue seems like part of it, but might not necessarily fix the concat issue.

The function cudf.utils.dtypes.find_common_type raises a TypeError when passed a cudf.ListDtype as one of the types.

Steps/Code to reproduce bug
Follow this guide http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports to craft a minimal bug report. This helps us reproduce the issue you're having and resolve the issue more quickly.

import cudf
from cudf.utils.dtypes import find_common_type
import numpy as np

find_common_type({cudf.ListDtype("int64")})
# Raises TypeError: issubclass() arg 1 must be a class

find_common_type({cudf.ListDtype("int64"), np.dtype("int64")})
# Raises TypeError: issubclass() arg 1 must be a class

This results in issues with

• concat of series with list and scalar types
  • described in [BUG] Concat of List column with scalar column results in issubclass TypeError #12083
• frame.values
  • cudf.DataFrame({"a": [[1]]}).values # Raises TypeError
• series.to_numpy
  • cudf.Series([[1]]).to_numpy() # Raises TypeError

Expected behavior

A common type returned when a list dtype is used.

Environment overview (please complete the following information)

• Environment location: [Bare-metal, Docker]
• Method of cuDF install: [conda, docker]
  • docker :: docker run -it --gpus=all --rm nvcr.io/nvidia/rapidsai/rapidsai:22.10-cuda11.5-runtime-ubuntu20.04-py3.8 bash
  • conda :: conda create -n python-3.8-rapids-22.10 -c rapidsai -c nvidia -c conda-forge rapids=22.10 python=3.8 cudatoolkit=11.7