Repository: kubernetes
Issue: [flaky test] [It] [sig-network] Services should implement NodePort and HealthCheckNodePort correctly when ExternalTrafficPolicy changes
Labels: sig/network,kind/flake,needs-triage

### Which jobs are flaking?

pull-kubernetes-e2e-gce:
[failed run](https://prow.k8s.io/view/gs/kubernetes-ci-logs/pr-logs/pull/125932/pull-kubernetes-e2e-gce/1867982328341467136)
[succeeded run](https://prow.k8s.io/view/gs/kubernetes-ci-logs/pr-logs/pull/125932/pull-kubernetes-e2e-gce/1868009010649632768)

on PR [strategicpatch] support duplicated mergeKey values #125932 

### Which tests are flaking?

Kubernetes e2e suite: [It] [sig-network] Services should implement NodePort and HealthCheckNodePort correctly when ExternalTrafficPolicy changes

### Since when has it been flaking?

since my last commit in PR, maybe earlier in the same PR (there was a flaky test in the same PR, but i cant remember which exactly)

### Testgrid link

https://prow.k8s.io/view/gs/kubernetes-ci-logs/pr-logs/pull/125932/pull-kubernetes-e2e-gce/1867982328341467136

### Reason for failure (if possible)

Possibly failing because of changes introduced in PR.

Test log says:
```
I1214 17:43:45.840527 65508 service.go:4068] Unexpected error: updating ExternalTrafficPolicy and HealthCheckNodePort: 
    <*fmt.wrapError | 0xc00152a9e0>: 
    failed to update Service "external-local-update": Internal error occurred: failed to allocate requested HealthCheck NodePort 31865: provided port is already allocated
    {
        msg: "failed to update Service \"external-local-update\": Internal error occurred: failed to allocate requested HealthCheck NodePort 31865: provided port is already allocated",
        err: <*errors.StatusError | 0xc007ae3540>{
            ErrStatus: {
                TypeMeta: {Kind: "", APIVersion: ""},
                ListMeta: {
                    SelfLink: "",
                    ResourceVersion: "",
                    Continue: "",
                    RemainingItemCount: nil,
                },
                Status: "Failure",
                Message: "Internal error occurred: failed to allocate requested HealthCheck NodePort 31865: provided port is already allocated",
                Reason: "InternalError",
                Details: {
                    Name: "",
                    Group: "",
                    Kind: "",
                    UID: "",
                    Causes: [
                        {
                            Type: "",
                            Message: "failed to allocate requested HealthCheck NodePort 31865: provided port is already allocated",
                            Field: "",
                        },
                    ],
                    RetryAfterSeconds: 0,
                },
                Code: 500,
            },
        },
    }
[FAILED] updating ExternalTrafficPolicy and HealthCheckNodePort: failed to update Service "external-local-update": Internal error occurred: failed to allocate requested HealthCheck NodePort 31865: provided port is already allocated
```

This PR changes the way elements duplicated by the MergeKey value are handled on patch. 
Specifically, ports are such elements, so i guess possible causes may be: 
- ports are handled incorrectly
- my changes in PR are unstable and may produce invalid results in some cases

### Anything else we need to know?

_No response_

### Relevant SIG(s)

/sig network