Prevent an empty choice list being passed in debug:container

Hi guys!

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | --
| License       | MIT
| Doc PR        | n/a

Currently, there is a "bug" where if you pass an empty array to ChoiceList, then you get this following warning from `QuestionHelper::doAsk()`:

>
Warning: max(): Array must contain at least one element

That should probably be fixed too, but it would go on an earlier version, so I didn't want to mix fixes for different branches.

Thanks!