fix(contracts): improve DelayedWETH loading for fork tests

[ajsutton]

This PR fixes several issues with how DelayedWETH addresses are loaded during fork-based upgrade tests.

Changes

Load pre-upgrade state from on-chain queries

• Changed upgrade tests to fetch DelayedWETH addresses directly from on-chain state using DisputeGames.getGameImplDelayedWeth() instead of relying on artifacts
• This makes the tests more robust and ensures they work correctly regardless of whether artifacts were properly populated

Fix v1/v2 OPCM structure handling

• Improved fallback logic in ForkLive._readSuperchainRegistry() to properly handle both v1 and v2 OPCM structures:
  • V1 structure: DelayedWETH accessed via gameImpl.weth()
  • V2 structure: DelayedWETH accessed via gameArgs().weth
• The code now attempts v2 first, then falls back to v1 if gameArgs don't exist or return empty bytes
• Ensures proper error propagation when gameArgs data is invalid

Fix copy-paste bug in ForkLive

• Fixed bug where permissionless DelayedWETH was being fetched using GameTypes.PERMISSIONED_CANNON instead of GameTypes.CANNON
• This caused incorrect artifact addresses to be saved

Improve test error messages

• Added descriptive error messages to WETH assertions to make test failures easier to diagnose

Testing

• All upgrade tests now pass with these changes
• Tests work correctly across all feature variants including CUSTOM_GAS_TOKEN

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.5%. Comparing base (e0340d6) to head (47fd02a).
⚠️ Report is 2 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #19206      +/-   ##
===========================================
+ Coverage     66.4%    81.5%   +15.1%     
===========================================
  Files           55      134      +79     
  Lines         4030     6930    +2900     
===========================================
+ Hits          2677     5651    +2974     
- Misses        1209     1279      +70     
+ Partials       144        0     -144     

Flag	Coverage Δ
cannon-go-tests-64	?
contracts-bedrock-tests	81.5% <ø> (?)

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see 189 files with indirect coverage changes

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