Support kwargs in partial objects passed to Initializer()

[jsiirola]

Fixes # .

Summary/Motivation:

@dallan-keylogic pointed out that Initializer() incorrectly maps functools.partial objects to IndexedCallInitializer when all the rule arguments are passed to functools.partial() as keyword arguments. This PR corrects this (and adds a test).

Changes proposed in this PR:

• Initializer() should detect positional arguments specified as keyword arguments to partial()
• Add a test of this behavior

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[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (99dc0f1) 87.83% compared to head (24170c2) 87.83%.
Report is 11 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2960   +/-   ##
=======================================
  Coverage   87.83%   87.83%           
=======================================
  Files         770      770           
  Lines       89657    89660    +3     
=======================================
+ Hits        78747    78754    +7     
+ Misses      10910    10906    -4     

Flag	Coverage Δ
linux	84.86% <100.00%> (-0.01%)	⬇️
osx	74.58% <100.00%> (+<0.01%)	⬆️
other	85.04% <100.00%> (+<0.01%)	⬆️
win	82.12% <100.00%> (+0.01%)	⬆️

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Files Changed	Coverage Δ
pyomo/core/base/initializer.py	98.71% <100.00%> (+0.01%)	⬆️

... and 3 files with indirect coverage changes

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