Introduce Valued Variables in logprob IR

[ricardoV94]

This simplifies the rewrite logic quite a bit and fixes #6917

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📚 Documentation preview 📚: https://pymc--6918.org.readthedocs.build/en/6918/

[codecov]

Codecov Report

Attention: Patch coverage is 58.63454% with 309 lines in your changes missing coverage. Please review.

Project coverage is 63.19%. Comparing base (ec4407d) to head (ff59803).
Report is 462 commits behind head on main.

Files with missing lines	Patch %	Lines
pymc/distributions/transforms.py	53.17%	162 Missing ⚠️
pymc/logprob/scan.py	9.25%	49 Missing ⚠️
pymc/logprob/mixture.py	21.73%	18 Missing ⚠️
pymc/logprob/transforms.py	64.00%	18 Missing ⚠️
pymc/logprob/tensor.py	46.15%	14 Missing ⚠️
pymc/pytensorf.py	65.00%	14 Missing ⚠️
pymc/logprob/basic.py	76.19%	10 Missing ⚠️
pymc/logprob/abstract.py	70.83%	7 Missing ⚠️
pymc/logprob/utils.py	91.66%	6 Missing ⚠️
pymc/logprob/binary.py	40.00%	3 Missing ⚠️
... and 5 more

❗ There is a different number of reports uploaded between BASE (ec4407d) and HEAD (ff59803). Click for more details.

HEAD has 9 uploads less than BASE

Flag	BASE (ec4407d)	HEAD (ff59803)
	14	5

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #6918       +/-   ##
===========================================
- Coverage   87.78%   63.19%   -24.59%     
===========================================
  Files         100      100               
  Lines       16896    16736      -160     
===========================================
- Hits        14832    10577     -4255     
- Misses       2064     6159     +4095     

Files with missing lines	Coverage Δ
pymc/distributions/mixture.py	33.61% <100.00%> (-61.37%)	⬇️
pymc/distributions/multivariate.py	50.00% <100.00%> (-7.48%)	⬇️
pymc/gp/cov.py	98.00% <100.00%> (ø)
pymc/gp/util.py	96.47% <100.00%> (+0.04%)	⬆️
pymc/initial_point.py	100.00% <100.00%> (ø)
pymc/logprob/rewriting.py	93.47% <100.00%> (+3.36%)	⬆️
pymc/model/core.py	64.97% <100.00%> (-26.78%)	⬇️
pymc/model/fgraph.py	25.25% <100.00%> (-71.65%)	⬇️
pymc/model/transform/conditioning.py	17.20% <100.00%> (-78.49%)	⬇️
pymc/logprob/censoring.py	63.52% <75.00%> (-35.35%)	⬇️
... and 14 more

... and 38 files with indirect coverage changes

[ricardoV94]

Closing in favor of #7491