fix incorrect variable usage in bytes decoding function

[emmanuel-ferdman]

PR Summary

PR fixes variable usage in ExtendJSONEncoderBytes from 'o' to 'obj'.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 78.35%. Comparing base (8d96dc2) to head (0456411).

Files with missing lines	Patch %	Lines
common/utils/extend_json_encoder.py	0.00%	1 Missing :warning:

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2821   +/-   ##
=======================================
  Coverage   78.35%   78.35%           
=======================================
  Files         124      124           
  Lines       17580    17580           
=======================================
  Hits        13775    13775           
  Misses       3805     3805           

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[LeoQuote]

Thanks for your pr! Please add tests for the change so it can be safely merged.