ci(gha): pin windows cmake to 3.31.6

[scotthart]

github rolled out a VM update that included cmake 4.0 by default, which caused build failures.

Also the storage, storage_grpc Debug build was running out of space. We'll see if splitting them into two builds helps any.

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This change is 

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.90%. Comparing base (dd5d662) to head (39a41ce).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15061   +/-   ##
=======================================
  Coverage   92.90%   92.90%           
=======================================
  Files        2354     2354           
  Lines      210374   210374           
=======================================
+ Hits       195446   195456   +10     
+ Misses      14928    14918   -10     

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