Create a test passing in an ESR payload w/ meta data and ensure metadata persists

[Aaron Cox]

I'm not sure if when you pass in an ESR payload, that the metadata will persist. The createRequest method takes the request body and creates a new SigningRequest object with it, which may disregard all the old information it contained.

https://github.com/wharfkit/session/blob/dev/src/session.ts#L291-L321

A test should be added that passes a request with metadata, and then ensures the metadata makes it through the entire process.

If it doesn't, then perhaps we need to clone the request instead of creating a new one?