Pin dask to avoid 2024.8.0 - problems with masked fill/missing values

[valeriupredoi]

Description

Closes #2503

I will also open an issue at Dask with an MRC, but this is all we can do, for now, at our end

So far, this is an iris issue reported here SciTools/iris#6109

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.71%. Comparing base (9636505) to head (8439463).
Report is 45 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2504   +/-   ##
=======================================
  Coverage   94.71%   94.71%           
=======================================
  Files         249      249           
  Lines       14123    14123           
=======================================
  Hits        13376    13376           
  Misses        747      747           

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[valeriupredoi]

gents @bouweandela @schlunma shall we merge this until the good folk at iris figure out how to fix the issue? 🍺

[bouweandela]

Thanks V! 🍻