bugfix: problem in import service with missing "Continue" keyword in the HTTP/1.1 100 header

[hboie]

when the server doesn't send the "Continue" keyword in the "HTTP/1.1 100" header, this header will not be stripped correctly.

Then also the rest of the header will not be stripped correctly, but ends up in the response_body, which causes an expection
when trying to convert the JSON data of the response_body.

[david-puente]

I solve this with:

    $header_size = curl_getinfo($curlHandle, CURLINFO_HEADER_SIZE);
    $this->response_headers = substr($response, 0, $header_size);
    $this->response_body = substr($response, $header_size);