Remove (part of) the remaining Pyomo 6.6.2 deprecations

[lbianchi-lbl]

Fixes #1227

Summary/Motivation:

Some uses of pyomo.core.current.expr have a different import syntax and were not caught by #1234.

Changes proposed in this PR:

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[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01% ⚠️

Comparison is base (5a9ead4) 76.59% compared to head (95a9484) 76.59%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1247      +/-   ##
==========================================
- Coverage   76.59%   76.59%   -0.01%     
==========================================
  Files         382      382              
  Lines       60822    60822              
  Branches    11200    11200              
==========================================
- Hits        46587    46584       -3     
- Misses      11818    11822       +4     
+ Partials     2417     2416       -1     

Files Changed	Coverage Δ
idaes/core/plugins/simple_equality_eliminator.py	86.44% <100.00%> (ø)
idaes/core/plugins/variable_replace.py	100.00% <100.00%> (ø)
idaes/core/surrogate/pysmo/utils.py	92.59% <100.00%> (ø)
idaes/core/util/expr_doc.py	13.96% <100.00%> (ø)
idaes/core/util/scaling.py	88.47% <100.00%> (ø)

... and 1 file with indirect coverage changes

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[andrewlee94]

Note that I also fixed these issues in #1228, sp if that gets merged first this PR will become moot.