Mark incompatible dask-python-combination-tests as XFail

[glatterf42]

We can currently observe an incompatibility of dask with python 3.11.9 e.g. in the message-ix-models CI. This is fixed in version 2024.4.1 of dask, but our CI runs pip install .[docs,tests] "dask < 2024.3.0" "genno < 1.25" "pandas < 2.0" "pytest == 8.0.0" for message-ix-models with message_ix 3.6.0 and below. We expect that removing the pin for the dask version entails solving a dependency mess since we would need to adhere to requiring dask-expr. So for now, we opt to XFail the test depending on dask instead.

How to review

@khaeru, should I mention this PR in a comment in-line? I'm not sure what else to reference there.

• Read the diff and note that the CI checks all pass.

PR checklist

• [x] Continuous integration checks all ✅
• [x] Update tests; coverage checks both ✅
• ~[ ] Add, expand, or update documentation.~ Just test suite changes.
• ~[ ] Update doc/whatsnew.~ Just test suite changes.

[codecov[bot]]

Codecov Report

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

Project coverage is 75.6%. Comparing base (7dc5385) to head (c209537). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #165 +/- ## ===================================== Coverage 75.5% 75.6% ===================================== Files 101 101 Lines 6675 6683 +8 ===================================== + Hits 5046 5054 +8 Misses 1629 1629 ``` | [Files](https://app.codecov.io/gh/iiasa/message-ix-models/pull/165?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa) | Coverage Δ | | |---|---|---| | [message\_ix\_models/tests/tools/iea/test\_web.py](https://app.codecov.io/gh/iiasa/message-ix-models/pull/165?src=pr&el=tree&filepath=message_ix_models%2Ftests%2Ftools%2Fiea%2Ftest_web.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-bWVzc2FnZV9peF9tb2RlbHMvdGVzdHMvdG9vbHMvaWVhL3Rlc3Rfd2ViLnB5) | `100.0% <100.0%> (ø)` | |