Pim 3326 stable : Fix mongo filters with multiples values and empty

| Q                    | A
| -------------------- | ---
| Bug fix?             | Y
| New feature?         | N
| BC breaks?           | N
| CI currently passes? | ?
| Tests pass?          | ?
| Scenarios pass?      | ?
| Checkstyle issues?*  | N
| PMD issues?**        | N
| Changelog updated?   | N
| Fixed tickets        | PIM-3326
| DB schema updated?   | N
| Migration script?    | N
| Doc PR               | N
count($value) > 1 is unnecessary : if the array contains 'empty', there is at least one element.