Make asarray work with array-api-compat CuPy arrays

[mdhaber]

This should work:

from array_api_compat import cupy as cp
import marray
mcp = marray._get_namespace(cp)
x = cp.asarray([1, 2, 3])
mcp.asarray(x)  # ValueError: Unsupported dtype object

This happens because x has an attribute data, but cp.asarray(x.data) doesn't work (like it does for NumPy).
asarray (and other functions) probably shouldn't be using the data attribute of an object just because it exists; we only really mean to do that if the array has a mask.