Fix failing tests with latest version of packmol

[CalCraven]

Update packmol arguments to raise Errors on overlapping molecules on overpacked boxes, and reduce overlaps argument for test cases.

PR Summary:

PR Checklist

---

• Includes appropriate unit test(s)
• Appropriate docstring(s) are added/updated
• Code is (approximately) PEP8 compliant
• Issue(s) raised/addressed?

[chrisjonesBSU]

LGTM, thanks!

[chrisjonesBSU]

The windows version of PACKMOL on conda-forge is very out-dated, so at some point if the differences of released versions become too large, we might not be able to support both in the CI workflow. This came up as a problem in #787

[daico007]

should we scrap the windows CI?

[chrisjonesBSU]

should we scrap the windows CI?

IMO, I think we should.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.41%. Comparing base (2bb047e) to head (db6334d).
Report is 44 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1189      +/-   ##
==========================================
+ Coverage   87.32%   87.41%   +0.09%     
==========================================
  Files          62       62              
  Lines        6525     6540      +15     
==========================================
+ Hits         5698     5717      +19     
+ Misses        827      823       -4     

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