Late controller flashes translation

| Q                    | A
| -------------------- | ---
| Bug fix?             | no
| New feature?         | no
| BC breaks?           | no
| CI currently passed? | no
| Tests pass?          | yes
| Scenarios pass?      | yes
| Checkstyle issues?   | no
| Changelog updated?   | no
| Fixed tickets        |
| Doc PR               |

AbstractController could be lighten by removing the dependency on translator, but it would break BC.
Flash messages are created in controller so I don't think it's wise to put the model class into the datagrid bundle