Fix length calculation with skipped file

            // text part size

            length += data.length;

            // file size

            long fileSize = ImageHelper.getFileSize(context, uri);

            if (fileSize <= UPLOAD_SIZE_MAX && fileSize > 0) {

                String headers = String.format(MULTIPART_FILE_TEMPLATE, PARAM_IMAGE, fileMime);

                length += headers.getBytes(StandardCharsets.UTF_8).length + delimiter.length;

            length += ImageHelper.getFileSize(context, uri);

                length += fileSize;

            }

            // closing delimiter

            length += delimiter.length + 2;

        }