Fix rewrite weakref leak

[ricardoV94]

Decorating methods with lru_cache causes a leak. Fixed as suggested in https://rednafi.com/python/lru-cache-on-methods/

This was present for a while, but was made worse in #1594 when we switched from lru_cache which has a default limit of 128 to cache which can grow without bounds. (h/t to @jessegrabowski who suggested the change)

This caused a failure downstream in PyMC in a test that checks for similar sort of leak.

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📚 Documentation preview 📚: https://pytensor--1660.org.readthedocs.build/en/1660/

[jessegrabowski]

Great catch, very subtle bug.

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 81.56%. Comparing base (db5178b) to head (7a90d3d).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
pytensor/graph/rewriting/basic.py	66.66%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (66.66%) is below the target coverage (100.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1660      +/-   ##
==========================================
- Coverage   81.56%   81.56%   -0.01%     
==========================================
  Files         242      242              
  Lines       53818    53819       +1     
  Branches     9485     9485              
==========================================
  Hits        43899    43899              
- Misses       7430     7431       +1     
  Partials     2489     2489              

Files with missing lines	Coverage Δ
pytensor/graph/rewriting/basic.py	72.19% <66.66%> (-0.06%)	⬇️

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