Overhaul implementation of AutoSlots.__deepcopy__

[jsiirola]

Fixes # .

Summary/Motivation:

This resolves some lingering issues when deepcopying AutoSlot classes / Pyomo models.

• Ensure that the temporary state created when deepcopying Components is preserved until deepcopy is finished. This is a more robust solution to a patch that was introduced in Fix bug in AutoSlots deepcopy #3412
• Remove redundant deepcopy implementations (standardize all logic in AutoSlots)
• Fix a minor logic error when determining if components are in/out of the __block_scope__
• Minor performance improvements (enough so that pmedian8 runs slightly faster, even after the additional overhead of keeping the temporary states alive)

Changes proposed in this PR:

• (see above)

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1. I agree my contributions are submitted under the BSD license.
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.66%. Comparing base (fe3f83f) to head (57e6082).
Report is 24 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3413      +/-   ##
==========================================
+ Coverage   84.77%   88.66%   +3.89%     
==========================================
  Files         879      879              
  Lines      100380   100383       +3     
==========================================
+ Hits        85097    89006    +3909     
+ Misses      15283    11377    -3906     

Flag	Coverage Δ
linux	86.12% <100.00%> (?)
osx	76.11% <100.00%> (?)
other	86.61% <100.00%> (?)
win	84.50% <100.00%> (?)

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