Bump pytest to 8.0

[bunchesofdonald]

First check

• [X] I am a contributor to the Prefect codebase

Description

pytest 8.0 was just released and added some deprecations that affect the Prefect test suite. We should bump pytest to 8.0, fix any deprecation warnings, and ensure the test suite runs as expected.

Impact

No response

Additional context

No response

[serinamarie]

Closed by https://github.com/PrefectHQ/prefect/pull/11821

[bunchesofdonald]

We actually had to revert this due to compatibility issue with ddtrace. We should bump pytest to 8 when that compatibility is fixed.