updating for open data format change

[kbuma]

Summary

Updating the OpenDataStore to work with the changes in the format for storing the data in Open Data.

Checklist

• Google format doc strings added.
• Code linted with ruff. (For guidance in fixing rule violates, see rule list)
• Type annotations included. Check with mypy.
• Tests added for new features/fixes.
• I have run the tests locally and they passed.

[codecov]

Codecov Report

Attention: 108 lines in your changes are missing coverage. Please review.

Comparison is base (5bd33b3) 82.98% compared to head (6baf8bc) 81.54%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
src/maggma/stores/open_data.py	0.00%	108 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #911      +/-   ##
==========================================
- Coverage   82.98%   81.54%   -1.44%     
==========================================
  Files          46       46              
  Lines        3878     3939      +61     
==========================================
- Hits         3218     3212       -6     
- Misses        660      727      +67     

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