flake8 6.1.0 fixes

[ndgrigorian]

This PR aims to fix dpctl's flake8 style conformity and the flake8 CI, which have both been changed by flake8 releasing version 6.1.0.

Checks for equality between types (i.e., type(x) == type(y)) have been changed to use the is keyword to that end.

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[github-actions]

View rendered docs @ https://intelpython.github.io/dpctl/pulls/1312/index.html

[coveralls]

coverage: 84.776%. remained the same when pulling 99c4a4a on fix-for-flake8-610 into 45ed4d5 on master.

[github-actions]

Array API standard conformance tests for dpctl=0.14.6dev0=py310h7bf5fec_58 ran successfully.
Passed: 595
Failed: 405
Skipped: 119

[oleksandr-pavlyk]

LGTM. Thank you @ndgrigorian

[github-actions]

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

[github-actions]

Array API standard conformance tests for dpctl=0.14.6dev0=py310h7bf5fec_57 ran successfully.
Passed: 594
Failed: 406
Skipped: 119