Fixes bug with IndexedSet objects and the within argument

[thisandthatuser]

Fixes #3284 .

Summary/Motivation:

Indexed sets relying on other indexed sets for the within argument trigger errors in pyomo 6.7.3, whereas in pyomo 6.6.x they did not.

Changes proposed in this PR:

• Fixed the bug
• Added tests to ensure future functionality changes are noticed
• Updated the set tutorial
• Updated the doc string to be more explicit about this functionality

Legal Acknowledgement

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[thisandthatuser]

The tests are failling because of numpy v2, which is being handled already in #3291

[jsiirola]

This is a great catch and I am impressed that the fix was that straightforward. I have a couple minor requests for edits (one is a slight modification to your fix, and the other updates the tests to make better / more standard use of unittest).

note that this PR will conflict with #3302. I propose that (assuming you have time), we get this PR updated and merged first and then I will update #3302.

[mrmundt]

@thisandthatuser - can you please run the following on your code:

 # Auto-apply correct formatting
pip install black
black -S -C <path> --exclude examples/pyomobook/python-ch/BadIndent.py

If you already have black installed, please make sure it's on the latest version!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.48%. Comparing base (b50cfac) to head (643c0e5).
Report is 17 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3288   +/-   ##
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  Coverage   88.48%   88.48%           
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  Files         868      868           
  Lines       98427    98428    +1     
=======================================
+ Hits        87095    87097    +2     
+ Misses      11332    11331    -1     

Flag	Coverage Δ
linux	86.30% <100.00%> (+<0.01%)	⬆️
osx	75.61% <100.00%> (+<0.01%)	⬆️
other	86.49% <100.00%> (+<0.01%)	⬆️
win	83.80% <100.00%> (+<0.01%)	⬆️

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