Investigate removing pytest upper bound pinnings

[vyasr]

When pytest 8 was released it broke a number of popular pytest plugins. As a result, various RAPIDS projects introduced upper bound pinnings, e.g. rapidsai/cudf#14920. We should investigate removing those pinnings and see if we still have issues. IIRC in addition to compatibility with plugins, there were also changes to pytest's import machinery, specifically the --import-mode flag, and we may need to do some work in certain RAPIDS repositories to make their test suite compatible with those changes even if the upstream plugins have been adapted. That work should be done by the relevant teams.