Fix broken doctest and tests on accessors

[weiji14]

Couple of tests to fix when running pytest --verbose --doctest-modules cupy_xarray:

• On cupy_xarray.accessors.CupyDataArrayAccessor.as_cupy, output type should now be cupy.ndarray instead of cupy.core.core.ndarray
• There was an error like ModuleNotFoundError: No module named 'xarray.core.pycompat' when running on xarray=2024.6.0. Need to apply a patch similar in concept to Fix broken dask_array_type import #24, but without importing xarray.core.pycompat (since it is a private function?). Specifically, change the from xarray.core.pycompat import dask_array_type line to:

  try:
      import dask.array
  
      dask_array_type = dask.array.Array
  except ImportError:
      dask_array_type = None

Partially cherry-picked from #45. These changes will need to be tested locally with a CUDA GPU device for now, until we can get CI working somehow.

[dcherian]

Let's just not do that

Suggested change

	dsk = DuckArrayModule("dask")
	dask_array_type = dsk.type
	try:
	import dask.array
	dask_array_type = dask.array.Array
	else:
	dask_array_type = None

There is some new importlib way of doing this that I can't remember now

[weiji14]

Ok, done at 6229f99.

There is some new importlib way of doing this that I can't remember now

Do you mean importlib.util.find_spec? That would allow us to get to the dask.array module, but not the dask.array.Array type. Unless there's another function I'm missing.

[dcherian]

yeah that one but maybe it's not a big deal here/