[INFRA]: Make RAPIDS CI jobs required to pass before a release

### Is this a duplicate?

- [x] I confirmed there appear to be no [duplicate issues](https://github.com/NVIDIA/cccl/issues) for this request and that I agree to the [Code of Conduct](CODE_OF_CONDUCT.md)

### Overview

RAPIDS CI jobs should be required to pass before we cut a finalized CCCL release.

### Details

RAPIDS CI jobs are currently optional in per-PR workflows. It would likely be too noisy to make them required before merging a PR, but we should make it required before finalizing a release.