Fix bug in deserializing counterfactual explainer

[gaugup]

Description

The deserializing of the counterfactual had a bug which was causing the retraining of counterfactual explainer during load().

Checklist

• I have added screenshots above for all UI changes.
• I have added e2e tests for all UI changes.
• Documentation was updated if it was needed.

[codecov-commenter]

Codecov Report

Merging #1554 (ac3cb9e) into main (b1cf129) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1554   +/-   ##
=======================================
  Coverage   87.73%   87.73%           
=======================================
  Files         109      109           
  Lines        5260     5261    +1     
=======================================
+ Hits         4615     4616    +1     
  Misses        645      645           

Flag	Coverage Δ
unittests	87.73% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...i/responsibleai/managers/counterfactual_manager.py	93.97% <100.00%> (+0.01%)	⬆️

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[github-actions]

https://responsibleai.blob.core.windows.net/pullrequest/microsoft/responsible-ai-toolbox/gaugup/FixCFExplainerLoading/dashboard/index.html

[imatiach-msft]

is there some way to add a test to validate the explainer is not getting re-trained on load?