BUG: fix Heasarch.locate_data returning empty rows

[zoghbi-a]

Heasarc.locate_data returns empty rows with an error in the error_message column if there are no data associated with that row rather than filtering it out. fixes #3271.

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 69.37%. Comparing base (9dca39b) to head (af2d6f4).
Report is 175 commits behind head on main.

Files with missing lines	Patch %	Lines
astroquery/heasarc/core.py	50.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3275   +/-   ##
=======================================
  Coverage   69.37%   69.37%           
=======================================
  Files         232      232           
  Lines       19684    19686    +2     
=======================================
+ Hits        13655    13657    +2     
  Misses       6029     6029           

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[bsipocz]

Could you please add some descriptive titles next time? It will make maintainers' life easier. Also, if possible please add labels and such. Thanks!

[bsipocz]

Thank you for this fix.