Previously the print job was sent with multiple PUT requests. This was necessary since the request was made with the Python Requests library, which freezes the interface while it's running. By breaking the upload up in chunks, it would at least periodically keep updating the interface (4 times per second or so, depending on your internet speed and Ultimaker's). Later on, this was replaced by a QNetworkRequest which doesn't freeze the interface in a refactor, but it was still broken up in chunks.
Recently that was again refactored to use Uranium's HttpRequestManager, which under the covers also uses QNetworkRequest. This also doesn't freeze while uploading, which is good. However for some reason the second chunk would always give a QNetworkReply::ProtocolUnknownError, which is a bit of a catch-all error for any HTTP status codes not supported by Qt. I was not able to figure out what was really going wrong there, but it has something to do with the content-range header and making multiple requests.
Instead of fixing that, I've removed the chunking. This simplifies the code a lot and doesn't have any implications for the user, since it still doesn't freeze the interface while the network request is ongoing. It should be slightly faster to upload, and reduce load on the server too.
However the disadvantage is that the original bug is probably still there if it was a bug in the HttpRequestManager. If it was a bug in the ToolPathUploader I probably deleted the bug here.
Contributes to issue CURA-7488.
