Remove 'reduce' from lib_depends, closes #19467

[jbrockmendel]

• closes Build no longer caching lib.pyx #19467
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[codecov]

Codecov Report

Merging #19472 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #19472      +/-   ##
==========================================
- Coverage    91.6%   91.59%   -0.01%     
==========================================
  Files         150      150              
  Lines       48724    48724              
==========================================
- Hits        44632    44630       -2     
- Misses       4092     4094       +2

Flag	Coverage Δ
#multiple	89.96% <ø> (-0.01%)	⬇️
#single	41.74% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
pandas/util/testing.py	83.64% <0%> (-0.21%)	⬇️

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[jreback]

thanks!