Fix invalid reference to ingress 'operatorMode' in validation.yaml

[bskim45]

Summary

This fixes the invalid reference to ingress operatorMode in validation.yaml. The correct reference to operatorMode should be .Values.ingressController.config.operatorMode.

Checklist:

• [ ] add related issues
• [ ] update Configuration in README
• [ ] update Changelog in README (major versions)
• [ ] update Upgrading in README (breaking changes)
• [x] ready for review

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