Fix bug where nested "bytes" property fails with TypeError

[ejizba]

If you try to send an http body with a nested "bytes" property that is a number it currently fails to execute.
Example request:

curl -X POST http://localhost:7071/api/helloWorld -d '{ "a": { "b": { "bytes": 4 }}}'

Error:

TypeError [ERR_INVALID_ARG_TYPE]: The first argument must be of type string or an instance of Buffer, ArrayBuffer, or Array or an Array-like Object. Received type number (4)

The root of the problem is a combination of our fromTypedData and convertKeysToCamelCase methods. I think both have some fundamental issues, but I'm wary of refactoring because it might break people relying on the existing behavior. For now, I think it's good enough for us to catch any error and use the original value. I will save bigger refactors for the new programming model.

Fixes Azure/azure-functions-nodejs-worker#607