Fixed PIM-3194

| Q                    | A
| -------------------- | ---
| Bug fix?             | Yes
| New feature?         | No 
| BC breaks?           | No
| CI currently passes? | ?
| Tests pass?          | Yes
| Scenarios pass?      | Yes
| Checkstyle issues?*  | No
| PMD issues?**        | No
| Changelog updated?   | Yes
| Fixed tickets        | PIM-3194
| DB schema updated?   | No
| Migration script?    | No
| Doc PR               | No

This is needed for the FeuVert DAM. It fixes entities collections being reordered on hydration.
In fact getting the result indexed by the identifier would be better as the following extraction into an indexed array would not be necessary.