Fix add Constant fold helper

[ricardoV94]

What is this PR about?

This PR refactors repeated constant fold logic into a helper function in aesaraf
Fixes the faulty just merged #6150, I forgot to push the latest local code

Checklist

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Major / Breaking Changes

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Bugfixes / New features

• Add constant_fold helper

Docs / Maintenance

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[codecov]

Codecov Report

Merging #6160 (ee51dc2) into main (75e9406) will increase coverage by 5.87%.
The diff coverage is 100.00%.

❗ Current head ee51dc2 differs from pull request most recent head dc1af3b. Consider uploading reports for the commit dc1af3b to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6160      +/-   ##
==========================================
+ Coverage   87.14%   93.01%   +5.87%     
==========================================
  Files          91       91              
  Lines       20717    20713       -4     
==========================================
+ Hits        18054    19267    +1213     
+ Misses       2663     1446    -1217     

Impacted Files	Coverage Δ
pymc/aesaraf.py	93.54% <100.00%> (ø)
pymc/distributions/logprob.py	97.26% <100.00%> (+7.92%)	⬆️
pymc/backends/base.py	86.44% <0.00%> (+0.73%)	⬆️
pymc/printing.py	86.08% <0.00%> (+0.86%)	⬆️
pymc/step_methods/slicer.py	96.20% <0.00%> (+1.26%)	⬆️
pymc/backends/report.py	91.04% <0.00%> (+4.47%)	⬆️
pymc/step_methods/hmc/quadpotential.py	80.69% <0.00%> (+7.67%)	⬆️
pymc/step_methods/arraystep.py	94.32% <0.00%> (+7.80%)	⬆️
pymc/sampling.py	82.19% <0.00%> (+12.08%)	⬆️
... and 6 more