Fix ./test/vendor/Initializable.t.sol test

[qzhodl]

Issue: The command forge test --match-path test/vendor/Initializable.t.sol failed because SoulGasToken is Initializable but does not pass the test_cannotReinitialize_succeeds check.

Solution:

• Add SoulGasToken to the test contracts list.
• Ensure it is deployed during testing (update hardhat.json accordingly).
• Add an initialize() call in SoulGasToken’s constructor. This is considered best practice and aligns with references:
  • OpenZeppelin guide
  • Optimism Style Guide
  • L2CrossDomainMessenger example