Contest card 기간순으로만 정렬

### Describe the problem and solution

기존 Registered 관련 카드 정렬 없애고 기간 순으로만 카드 정렬.

### Validations

- [X] Follow our [Code of Conduct](https://github.com/skkuding/next/blob/main/CODE_OF_CONDUCT.md)
- [X] Read the [Contributing Guidelines](https://github.com/skkuding/next/blob/main/CONTRIBUTING.md)
- [X] Check that there isn't already an issue