Replace contract body encoding from hex to utf8

[nozim]

Closes #1195

Description

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For contributor use:

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[turbolent]

Nice! Thank you

[chasefleming]

@nozim looks like this breaks the tests

[nozim]

@chasefleming will have a look. Thanks

[codecov-commenter]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (6dc3fec) 39.47% compared to head (f2f9fb9) 38.65%.
Report is 106 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1220      +/-   ##
==========================================
- Coverage   39.47%   38.65%   -0.83%     
==========================================
  Files          37       38       +1     
  Lines        1882     1948      +66     
==========================================
+ Hits          743      753      +10     
- Misses       1051     1107      +56     
  Partials       88       88              

Flag	Coverage Δ
unittests	38.65% <ø> (-0.83%)	⬇️

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see 7 files with indirect coverage changes

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