Upgrade gateway on Sepolia for westend

[yrong]

Resolves: https://linear.app/snowfork/issue/SNO-1398

• Upgrade Gateway with recent token contract
• Register WND on Sepolia
• Transfer WND to Sepolia
• Transfer WND back to AH

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 85.77%. Comparing base (674e33b) to head (fea5a76).
Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
contracts/src/upgrades/westend/Gateway20250311.sol	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1407      +/-   ##
==========================================
- Coverage   86.11%   85.77%   -0.35%     
==========================================
  Files          18       19       +1     
  Lines         742      745       +3     
  Branches      109      110       +1     
==========================================
  Hits          639      639              
- Misses         87       90       +3     
  Partials       16       16              

Flag	Coverage Δ
solidity	85.77% <0.00%> (-0.35%)	⬇️

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