fix(aws-lambda): handle event. isBase64Encoded

[michael-bouvy]

🔗 Linked issue

#1778

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

When POSTing a body to an AWS Lambda function, either using a function URL or behind an API Gateway, the event.body may be base64 encoded ; when this is the case, event.isBase64Encoded is set to true.

In such cases, body transmitted to local Nitro call should be base64 decoded.

Resolves #1778

📝 Checklist

• I have linked an issue or discussion.
• [] I have updated the documentation accordingly.

[pi0]

Thanks!

[michael-bouvy]

Thanks @pi0 for the merge, took me a while to find the root cause of my issues (with @sidebase/nuxt-auth) yesterday 😅