[Validator] gracefully handle transChoice errors

This validator annotation was throwing an error for me:

```
/** @Assert\Length(min=6, minMessage="Must be 6 characters") */
```

To avoid this error in the current code I would need to provide a message template that accommodates the minimum length being 1, even though that's not the case.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | ~
| License       | MIT
| Doc PR        | ~