feat: repalce legacytx.StdSignBytes with the aminojson sign mode handler in eip712

[mmsqe]

Description

Closes: #XXXX

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Author Checklist

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please add links to any relevant follow up issues.

I have...

• tackled an existing issue or discussed with a team member
• left instructions on how to review the changes
• targeted the main branch

[codecov]

Codecov Report

❌ Patch coverage is 61.45833% with 37 lines in your changes missing coverage. Please review.
✅ Project coverage is 65.18%. Comparing base (7e3ac37) to head (0bc836b).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
ante/cosmos/eip712.go	0.00%	25 Missing ⚠️
ethereum/eip712/encoding.go	79.31%	3 Missing and 3 partials ⚠️
ethereum/eip712/encoding_legacy.go	79.31%	3 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #860      +/-   ##
==========================================
- Coverage   65.24%   65.18%   -0.06%     
==========================================
  Files         317      317              
  Lines       21612    21674      +62     
==========================================
+ Hits        14101    14129      +28     
- Misses       6351     6379      +28     
- Partials     1160     1166       +6     

Files with missing lines	Coverage Δ
ethereum/eip712/types.go	92.74% <100.00%> (+0.52%)	⬆️
ethereum/eip712/encoding.go	76.37% <79.31%> (-1.81%)	⬇️
ethereum/eip712/encoding_legacy.go	74.02% <79.31%> (-1.16%)	⬇️
ante/cosmos/eip712.go	2.77% <0.00%> (-0.33%)	⬇️

... and 3 files with indirect coverage changes

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