Fix discarded logs on chunk upload failure

If the size of the decision logs buffered exceeeds that of `upload_size_limit_bytes`, the upload will be split into chunks. If one of the attempted uploads return with an error the chunk is stored in the "new" buffer and will be re-attempted at the next invocation of the `oneShot` method. However, once that is done the function returns, leaving any decisions left in the buffer to be discarded. This PR fixes that, preserving all failed chunk uploads to the buffer.

Signed-off-by: Anders Eknert <anders.eknert@bisnode.com>