Bump `pytest` to 8.0+

[kaxil]

closes https://github.com/apache/airflow/issues/37156

The issues mentioned in the above meta-task are fixed

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[eladkal]

There was an attempt in https://github.com/apache/airflow/pull/37151 it required several changes to some tests

[Taragolis]

There is less incompatibility then we have before. I also would recommend to bump minimal version to 8.1.x or even 8.2.x, there is plenty of the bugs in 8.0.x And maybe upper bound to <9, every time we need some time for adopt our tests to the changes in major pytest version

[kaxil]

Hopefully fixed all the issues 🤞