Check if response is a string or JSON when logging it

[misham]

This is in reference to this line: https://github.com/traceloop/openllmetry-ruby/blob/main/traceloop-sdk/lib/traceloop/sdk.rb#L57

The raw response from some of the models / services, especially when not using an SDK, is a string. Would be good to document that this function expects JSON or have it handle converting a string to JSON.

Assuming no one else gets to this, I'll work on a PR, along with some other suggestions, once I work with the gem more.

[nirga]

Yes please @misham! :)