feat: support decimal 128 and 256 json types

[LuQQiu]

Fix: #2872

[github-actions]

ACTION NEEDED
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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 77.89%. Comparing base (60797a6) to head (fc74ffe).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
rust/lance/src/arrow/json.rs	83.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2880      +/-   ##
==========================================
+ Coverage   77.87%   77.89%   +0.01%     
==========================================
  Files         231      231              
  Lines       70513    70528      +15     
  Branches    70513    70528      +15     
==========================================
+ Hits        54915    54939      +24     
+ Misses      12465    12456       -9     
  Partials     3133     3133              

Flag	Coverage Δ
unittests	77.89% <83.33%> (+0.01%)	⬆️

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