Update workaround for #145

[khaeru]

The regression is still present in xarray 2024.11.0, so relax the mark condition to apply to versions equal to or greater than 2024.10.0.

PR checklist

• [x] Checks all ✅
• ~Update documentation~ N/A, test changes only
• ~Update doc/whatsnew.rst~

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.85%. Comparing base (b6d92e1) to head (e7d3254). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #154 +/- ## ======================================= Coverage 99.85% 99.85% ======================================= Files 52 52 Lines 4705 4705 ======================================= Hits 4698 4698 Misses 7 7 ``` | [Files with missing lines](https://app.codecov.io/gh/khaeru/genno/pull/154?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Paul+Natsuo+Kishimoto) | Coverage Δ | | |---|---|---| | [genno/testing/\_\_init\_\_.py](https://app.codecov.io/gh/khaeru/genno/pull/154?src=pr&el=tree&filepath=genno%2Ftesting%2F__init__.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Paul+Natsuo+Kishimoto#diff-Z2Vubm8vdGVzdGluZy9fX2luaXRfXy5weQ==) | `100.00% <ø> (ø)` | |