Fix Dask handling for chunks with 1-wide dimension

[flying-sheep]

TODO: find other configurations where this doesn’t work and add to test cases.

[codecov]

Codecov Report

Attention: Patch coverage is 18.18182% with 36 lines in your changes missing coverage. Please review.

Project coverage is 84.23%. Comparing base (c34cb6d) to head (5812b9d).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/fast_array_utils/stats/_sum.py	16.27%	36 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (c34cb6d) and HEAD (5812b9d). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (c34cb6d)	HEAD (5812b9d)
	4	3

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #87       +/-   ##
===========================================
- Coverage   98.94%   84.23%   -14.71%     
===========================================
  Files          17       17               
  Lines         379      406       +27     
===========================================
- Hits          375      342       -33     
- Misses          4       64       +60     

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[codspeed-hq]

CodSpeed Performance Report

Merging #87 will degrade performances by 46.51%

_{Comparing pa/wtf-dask (5812b9d) with main (c34cb6d)}

Summary

❌ 1 regressions
✅ 159 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	test_stats_benchmark[2d-ax1-scipy.sparse.csr_array-float64-is_constant]	750.2 µs	1,402.5 µs	-46.51%