DetailedApiRequestError.toString() should print more information

I've often found the DetailedApiRequestError.jsonResponse to contain critically important information about errors...

Maybe we could just dump that as part of the error messages using toString(), if we pretty print it with indentation it probably doesn't matter so much if it's a huge blob.

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I'm not entirely sure if any APIs would include sensitive information in error messages that you wouldn't want to risk leaking into logs. But I suspect that's not the case, although it can never be excluded as users could be doing anything..