Fix issue #186: Create winners view V2

[cld-vasconcelos]

This pull request fixes #186.

The issue has been successfully resolved based on the following evidence:

1. The implementation exactly matches the requested JSON structure from the issue description, with all required fields (title, description, prize, voting_draw_end, winners with nested submission and picture data)

2. The query correctly filters for contests with winners using Contest.objects.filter(winners__isnull=False) and orders them by voting_draw_end as required

3. The implementation handles all key requirements:

• Only returns contests that have at least one winner (via the filter and checking winners list)
• Includes complete winner information including first/last name
• Includes the winning submission with picture details and vote count
• Orders results by contest end date
• Handles null prizes by converting to empty string

4. The comprehensive test suite validates:

• Correct data structure
• Proper ordering
• Vote counting
• Multiple contests and winners
• All required fields are present and properly formatted

5. The code is properly organized with clear type definitions and separation of concerns between queries and types

The changes provide a complete, working implementation that fulfills all requirements from the original issue description, with proper testing and type safety through GraphQL types.

Automatic fix generated by OpenHands 🙌