Don't throw exception if access token is in JSON

If params are passed as JSON (instead of array), check and see if the access token is part of the JSON.

If it is, do not throw the "You need to give parameters as array if you want to give the token within the URI" exception.

For my example, the URL I pass to `fetch()` has ?access_token=X as part of the URL string. I am passing my `$params` as a JSON string that also includes access_token.

Without this change, I'm not sure how #6 was passing JSON `$params` and not having this error be thrown.