Don't call a subprocess with VASP custodian

[Andrew-S-Rosen]

Summary of Changes

Call Custodian directly rather than via a subprocess for VASP.

FYI: @zulissimeta, I had to revert this PR due to issues with concurrent calculations in certain workflow engines. Once we solve the upstream issue in Custodian, I can re-merge this PR.

Requires:

• Ensure Custodian-based codes work without calls to os.chdir #1821
• Custodian > 2024.2.15

Checklist

• I have read the "Guidelines" section of the contributing guide. Don't lie! 😉
• My PR is on a custom branch and is not named main.
• I have added relevant, comprehensive unit tests.

Notes

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• When your code is ready for review, ping one of the active maintainers.

[codecov]

Codecov Report

Attention: Patch coverage is 90.90909% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 99.37%. Comparing base (d95086e) to head (f69d709).
Report is 1 commits behind head on main.

❗ Current head f69d709 differs from pull request most recent head e3e9936. Consider uploading reports for the commit e3e9936 to get more accurate results

Files	Patch %	Lines
src/quacc/calculators/vasp/vasp.py	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1850      +/-   ##
==========================================
- Coverage   99.40%   99.37%   -0.04%     
==========================================
  Files          81       81              
  Lines        3190     3181       -9     
==========================================
- Hits         3171     3161      -10     
- Misses         19       20       +1     

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