Add ```__array__``` attribute support to ```usm_ndarray```

The decision to implement a TypeError broke a significant amount of the sklearnex interfaces for dpctl tensors and has prevented us from properly upgrading to 0.20 support for nearly a half of a year. Instead of raising a TypeError suggesting to use ```asnumpy``` simply use asnumpy for the ```__array__``` method.

I expect that the solution in #1964 was a stopgap.  Was that the case?
 