PIM-3475: Fix attribute options sort order in import/export

| Q                    | A
| -------------------- | ---
| Bug fix?             | Y
| New feature?         | Y
| BC breaks?           | N : but it add sort_order column to export options
| CI currently passes? | ?
| Tests pass?          | Y
| Scenarios pass?      | Y
| Checkstyle issues?*  | N
| PMD issues?**        | N
| Changelog updated?   | Y
| Fixed tickets        | PIM-3475
| DB schema updated?   | N
| Migration script?    | N
| Doc PR               | N
it's a detail, but we try to put documentation of variables on one single line