Install dask-expr on CI

[hendrikmakait]

Closes #8554

• Tests added / passed
• Passes pre-commit run --all-files

[github-actions]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

    26 files   -      1      26 suites   - 1   9h 25m 24s ⏱️ + 7h 46m 50s
 4 048 tests +   198   3 935 ✅ +   267    110 💤  -    65  3 ❌ +3 
49 419 runs  +38 234  47 184 ✅ +37 248  2 232 💤 +1 123  3 ❌ +3 

For more details on these failures, see this check.

Results for commit 88a6ab4. ± Comparison against base commit 6687f7e.

This pull request skips 7 and un-skips 80 tests.

distributed.protocol.tests.test_highlevelgraph
distributed.shuffle.tests.test_graph
distributed.shuffle.tests.test_merge
distributed.shuffle.tests.test_merge_column_and_index
distributed.shuffle.tests.test_shuffle
distributed.shuffle.tests.test_shuffle_plugins
distributed.tests.test_dask_collections

distributed.cli.tests.test_dask_worker ‑ test_dashboard_non_standard_ports
distributed.deploy.tests.test_local ‑ test_bokeh[False]
distributed.deploy.tests.test_local ‑ test_bokeh[True]
distributed.deploy.tests.test_local ‑ test_bokeh_kwargs
distributed.deploy.tests.test_local ‑ test_duplicate_clients
distributed.deploy.tests.test_local ‑ test_ipywidgets
distributed.deploy.tests.test_local ‑ test_ipywidgets_loop
distributed.deploy.tests.test_subprocess ‑ test_raise_on_windows
distributed.diagnostics.tests.test_eventstream ‑ test_eventstream
distributed.diagnostics.tests.test_task_stream ‑ test_get_task_stream_plot
…

[milesgranger]

Thanks, @hendrikmakait!