Ranking question: role="list" container without list items (aria-required-children) #3840

Describe the bug
In the submit view, a ranking question has a container with role="list" whose direct children are not list items. axe reports this as aria-required-children (critical, WCAG 1.3.1 Info and Relationships). Screen readers announce a list with no items, followed by unrelated content.

In src/components/Questions/QuestionRanking.vue, div.question__content has role="list". Its children are div.ranking-unranked and div.ranking-ranked, which hold their own <ul> (rendered by TransitionGroup tag="ul") and a label paragraph. The real lists are the inner <ul> elements, and the ranked items additionally set role="listitem" on <li>.

To Reproduce

1. Create a form with a ranking question with two or more options.
2. Open the form to answer it (/apps/forms/<hash>/submit).
3. Run axe on the page, or inspect the accessibility tree of the question.
4. axe reports aria-required-children on div.question__content.

Expected behavior
The outer container is not a list. role="group" keeps its aria-labelledby, aria-describedby, aria-errormessage and aria-invalid. The two inner <ul> elements stay the lists, and each one is named after its section ("Your ranking", and the unranked pool). The redundant role="listitem" on <li> can go.

Nextcloud (please complete the following information):

• Nextcloud-Version: master
• Forms-Version: main (5.5.0-dev)

Additional context
Found while reviewing #3123 (conditional questions). It is not caused by that PR: a top-level ranking question on main has the same problem.