BUGFIX: Solver Refactor - Allow no objective

[mrmundt]

Fixes NA (but this is mentioned in #2574)

Summary/Motivation:

There was a bug reported in #2574 (comment) that points out that you can't use ipopt_v2 to solve something without an objective, which you technically can do in v1. This fixes that bug.

Changes proposed in this PR:

• Allow no objective
• Populate the number of objectives / constraints / params attributes on problem

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[codecov]

Codecov Report

Attention: Patch coverage is 99.02913% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 88.39%. Comparing base (0cc323a) to head (4164bbd).
Report is 14 commits behind head on main.

Files	Patch %	Lines
pyomo/repn/linear.py	94.73%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3181   +/-   ##
=======================================
  Coverage   88.38%   88.39%           
=======================================
  Files         846      846           
  Lines       94978    95043   +65     
=======================================
+ Hits        83947    84009   +62     
- Misses      11031    11034    +3     

Flag	Coverage Δ
linux	86.33% <94.11%> (-0.01%)	⬇️
osx	76.15% <94.11%> (+0.41%)	⬆️
other	86.53% <94.11%> (+<0.01%)	⬆️
win	83.82% <94.11%> (+0.01%)	⬆️

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[michaelbynum]

Thanks for fixing this @mrmundt. I left one comment below.