Print OP name for unnamed RVs instead of raising AssertionErrors

[lucianopaz]

Description

When trying to get the string representation of a model that has raw pytensor random variable OP's in it, instead of raising an AssertionError, try to print the OP's name between arrow brackets <>, just like what is already done for constant data.

The string representation doesn't have much of a docstring so I didn't add anything to it. I'm not sure if it's showcased anywhere either, so I didn't touch anythin doc related.

Related Issue

• Closes The model string representation fails if there are unnamed RVs in the graph #7427

Checklist

• Checked that the pre-commit linting/style checks pass
• Included tests that prove the fix is effective or that the new feature works
• Added necessary documentation (docstrings and/or example notebooks)
• If you are a pro: each commit corresponds to a relevant logical change

Type of change

• New feature / enhancement
• Bug fix
• Documentation
• Maintenance
• Other (please specify):

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.18%. Comparing base (f6d1b33) to head (dad7817).
Report is 97 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7428   +/-   ##
=======================================
  Coverage   92.18%   92.18%           
=======================================
  Files         103      103           
  Lines       17259    17263    +4     
=======================================
+ Hits        15910    15914    +4     
  Misses       1349     1349           

Files with missing lines	Coverage Δ
pymc/printing.py	86.98% <100.00%> (+0.36%)	⬆️