[fix][evaluation] fix npe&retry issue

[xueyizheng]

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[codecov]

Codecov Report

❌ Patch coverage is 86.66667% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...d/modules/evaluation/application/experiment_app.go	75.00%	1 Missing and 1 partial ⚠️

@@            Coverage Diff             @@
##             main     #528      +/-   ##
==========================================
- Coverage   77.33%   77.32%   -0.01%     
==========================================
  Files         657      657              
  Lines       73826    73835       +9     
==========================================
+ Hits        57091    57096       +5     
- Misses      13346    13348       +2     
- Partials     3389     3391       +2     

Flag	Coverage Δ
unittests	77.32% <86.66%> (-0.01%)	⬇️

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Files with missing lines	Coverage Δ
...modules/evaluation/application/eval_openapi_app.go	92.63% <100.00%> (+0.02%)	⬆️
...d/modules/evaluation/application/experiment_app.go	84.51% <75.00%> (+0.03%)	⬆️

... and 2 files with indirect coverage changes

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