add epsilon to eci inverse probability

[LittleLittleCloud]

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fix #6644

[codecov]

Codecov Report

Merging #6668 (5af13b6) into main (3d705bf) will increase coverage by 0.10%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6668      +/-   ##
==========================================
+ Coverage   68.67%   68.77%   +0.10%     
==========================================
  Files        1203     1215      +12     
  Lines      250974   251556     +582     
  Branches    26209    26228      +19     
==========================================
+ Hits       172350   173007     +657     
+ Misses      71800    71732      -68     
+ Partials     6824     6817       -7     

Flag	Coverage Δ
Debug	68.77% <100.00%> (+0.10%)	⬆️
production	63.28% <ø> (+0.12%)	⬆️
test	88.88% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
test/Microsoft.ML.AutoML.Tests/TunerTests.cs	100.00% <100.00%> (ø)

... and 36 files with indirect coverage changes