Include `correlation_context.request_id` in notice payload

[rabidpraxis]

If we have a request_id (we created it, or it came from a request), we should add it to the notice payload.

Here is the updated notice schema:

https://github.com/honeybadger-io/honeybadger-schemas/blob/45d5f9a91c6be69d43bb95722610d0df03046747/exceptions/v1/notices.json#L5-L16