Handle possible NULL return from DPCTLDevice_GetMaxWorkGroupSize1d, 2d

[oleksandr-pavlyk]

Python code now checks that the return value of DPCTLDevice_GetMaxWorkGroupSize1d and DPCTLDevice_GetMaxWorkGroupSize2d is not NULL before dereferencing.

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[github-actions]

Deleted rendered PR docs from intelpython.github.com/dpctl, latest should be updated shortly. 🤞

[coveralls]

coverage: 87.943% (-0.03%) from 87.971%
when pulling 3952ef7 on handle-possible-errors
into 183bfd7 on master.

[github-actions]

Array API standard conformance tests for dpctl=0.18.0dev0=py310h15de555_8 ran successfully.
Passed: 889
Failed: 16
Skipped: 91

[ndgrigorian]

LGTM!