[Build] Test on Python 3.14

[riedgar-ms]

Now that Python 3.14 is out, add it to the test matrix.

[codecov-commenter]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.26%. Comparing base (5b23547) to head (a31996a).
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❗ There is a different number of reports uploaded between BASE (5b23547) and HEAD (a31996a). Click for more details.

HEAD has 124 uploads less than BASE

Flag	BASE (5b23547)	HEAD (a31996a)
	127	3

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1385       +/-   ##
===========================================
- Coverage   77.26%   59.26%   -18.00%     
===========================================
  Files          62       62               
  Lines        5119     5119               
===========================================
- Hits         3955     3034      -921     
- Misses       1164     2085      +921     

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