chore: upgrade Serverless runtime to Node 22

[luislhl]

Motivation

We need Node 22 to support some recent changes in wallet-lib

Acceptance Criteria

• Serverless should deploy Lambdas with Node.js 22

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged
• Make sure either the unit tests and/or the QA tests are capable of testing the new features
• Make sure you do not include new dependencies in the project unless strictly necessary and do not include dev-dependencies as production ones. More dependencies increase the possibility of one of them being hijacked and affecting us.

[luislhl]

Closed in favor of #275