Format e2e contracts and ci check

[ferranbt]

📝 Summary

This PR formats the contracts in e2e and adds a CI check to validate them. You can format the contracts by running make fmt-contracts.

You can also use the Solidity vscode extension with this setting (vscode/settings.json) to format on save:

{
    "editor.formatOnSave": true,
    "[solidity]": {
        "editor.defaultFormatter": "JuanBlanco.solidity" 
      },
    "solidity.compileUsingRemoteVersion": "v0.8.16",
    "solidity.formatter": "forge",
    "solidity.packageDefaultDependenciesContractsDirectory": "src",
    "solidity.packageDefaultDependenciesDirectory": "lib"
}

📚 References

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• I have seen and agree to CONTRIBUTING.md