DRA: Variables in CEL

### Enhancement Description

- One-line enhancement description (can be used as a release note): Extend the CEL selector to support variables in DRA.
- Kubernetes Enhancement Proposal:
- Discussion Link: https://github.com/kubernetes/kubernetes/issues/125826
- Primary contact (assignee): cici37
- Responsible SIGs: wg-device-management
- Enhancement target (which target equals to which milestone):
- Alpha release target (x.y):
- Beta release target (x.y):
- Stable release target (x.y):
- [ ] Alpha
- [ ] KEP (`k/enhancements`) update PR(s):
- [ ] Code (`k/k`) update PR(s):
- [ ] Docs (`k/website`) update PR(s):

_Please keep this description up to date. This will help the Enhancement Team to track the evolution of the enhancement efficiently._