Fix label selector parsing for consecutive commas

[Xdynix]

Enhancement Description

• One-line enhancement description (can be used as a release note): Fix label selector parsing for consecutive commas.
• Kubernetes Enhancement Proposal: TODO
• Discussion Link: Fix label selector parsing for consecutive commas kubernetes#133419
• PRs by stage and milestone:
  • Alpha - v1.xx
    • KEP (k/enhancements) update PR(s): KEP-5483: Fix label selector parsing for consecutive commas #5484
    • Code (k/k) update PR(s): Fix label selector parsing for consecutive commas kubernetes#133419
    • Docs (k/website) update PR(s): TODO

[Xdynix]

/sig api-machinery