Drop NaN values in MAP_KEY column before align_partial_results

[ltiao]

Summary: NaN values in the progression column (MAP_KEY) cause align_partial_results to throw an exception that is silently caught, preventing early stopping from functioning. This change drops NaN rows early in _lookup_and_validate_data and logs a warning to alert users of potentially corrupted or missing progression data.

Differential Revision: D88750798

[meta-codesync]

@ltiao has exported this pull request. If you are a Meta employee, you can view the originating Diff in D88750798.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.53%. Comparing base (6cfd488) to head (c8b1b0b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4634      +/-   ##
==========================================
- Coverage   96.53%   96.53%   -0.01%     
==========================================
  Files         561      561              
  Lines       58175    58200      +25     
==========================================
+ Hits        56161    56185      +24     
- Misses       2014     2015       +1     

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[meta-codesync]

This pull request has been merged in b092b4d.