Ignore inner unused RNG inputs in collect_default_updates

[ricardoV94]

It closes the PyMC-side of #7657.

The example there will still not work due to the OpFromGraph L_op actually re-introducing the random variable (but not the next rng update). That's a PyTensor question, that may be addressed by pymc-devs/pytensor#1174

These changes still make sense on their own.

Closes #7657

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📚 Documentation preview 📚: https://pymc--7658.org.readthedocs.build/en/7658/

[codecov]

Codecov Report

Attention: Patch coverage is 95.23810% with 1 line in your changes missing coverage. Please review.

Project coverage is 92.78%. Comparing base (fa43eba) to head (16d5f13).

Files with missing lines	Patch %	Lines
pymc/pytensorf.py	95.23%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7658      +/-   ##
==========================================
- Coverage   92.78%   92.78%   -0.01%     
==========================================
  Files         107      107              
  Lines       18196    18207      +11     
==========================================
+ Hits        16884    16893       +9     
- Misses       1312     1314       +2     

Files with missing lines	Coverage Δ
pymc/pytensorf.py	90.67% <95.23%> (+<0.01%)	⬆️

... and 1 file with indirect coverage changes

[jessegrabowski]

Small typo, otherwise looks great

[jessegrabowski]

Suggested change

	# There we no more uses of this next_rng
	# There were no more uses of this next_rng