Change ConsensusPubkey type in staking precompile

[codchen]

Describe your changes and provide context

ethers would attempt to convert any string type field in a call response to unicode, which would fail for ConsensusPubkey since it contains non-readable bytes. The fix is to change ConsensuPubkey's type from string to bytes so that ethers don't attempt to convert it.

Testing performed to validate your change

test with ethers

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Jan 2, 2026, 6:18 PM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.29%. Comparing base (e6cb591) to head (736110c).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2646      +/-   ##
==========================================
+ Coverage   43.71%   46.29%   +2.57%     
==========================================
  Files        1902     1235     -667     
  Lines      158679   108109   -50570     
==========================================
- Hits        69372    50044   -19328     
+ Misses      82918    53468   -29450     
+ Partials     6389     4597    -1792     

Flag	Coverage Δ
sei-chain	45.69% <0.00%> (+<0.01%)	⬆️
sei-cosmos	?
sei-db	69.06% <0.00%> (ø)
sei-tendermint	47.28% <0.00%> (-0.02%)	⬇️

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see 691 files with indirect coverage changes

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