If a non-JSON message received contains quotes and is cut off weirdly, the following message might "quote" the line breaks. Then, we have an issue and cause \r\n\n for the further processing within the CodeOcean backend.
This change is required for Turtle output generated by the Python environment. Otherwise, drawing some images could add empty new lines (in the browser), since the original JSON message got split between the ending \r\n characters.
* This is based on Sentry issue CODEOCEAN-5W (linter translation failing due to \r in output)
* We cannot keep all "\r" messages but we must not forward the "\r" if it is a single message received after a valid JSON