fix(ingress): port.name matching failure for ExternalName Services

[AlinsRan]

Type of change:

• Bugfix
• New feature provided
• Improve performance
• Backport patches
• Documentation
• Refactor
• Chore
• CI/CD or Tests

What this PR does / why we need it:

---
apiVersion: [networking.k8s.io/v1](http://networking.k8s.io/v1)
kind: Ingress
metadata:
  name: httpbin
spec:
  rules:
  - host: [ingress.example.com](http://ingress.example.com/)
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: httpbin
            port:
              name: http
---
apiVersion: v1
kind: Service
metadata:
  name: httpbin
spec:
  type: ExternalName
  externalName: httpbin.org
  ports:
    - port: 8080
      protocol: TCP
      name: http

Expected to be 8080, actually 80.

Pre-submission checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[ronething]

others lgtm.