fix karmada instance aggregated service externalName error

[wawa0210]

What type of PR is this?

/kind bug

What this PR does / why we need it:

fix the latest Karmada-operator cannot install karmada instance

Which issue(s) this PR fixes:
Fixes #4209

Two bugs fixed in this pr

1. Karmada instance Aggregated service is installed on the correct namespace karmada-system
2. Fix karmada instance Aggregated service externalName to the correct value, which should be the service corresponding to karmada control plane

the example instance yaml

kubectl apply -f - <<EOF
apiVersion: operator.karmada.io/v1alpha1
kind: Karmada
metadata:
  name: karmada-demo
  namespace: test
EOF

the results

➜  karmada git:(master) ✗ kubectl get po -n test
NAME                                                    READY   STATUS    RESTARTS   AGE
karmada-demo-aggregated-apiserver-7bf4c5458f-zv4pz      1/1     Running   0          2m20s
karmada-demo-apiserver-65794cbd78-hmx99                 1/1     Running   0          2m41s
karmada-demo-controller-manager-69dbbcc866-nzxw6        1/1     Running   0          2m16s
karmada-demo-etcd-0                                     1/1     Running   0          2m43s
karmada-demo-kube-controller-manager-6949485b85-6d9mt   1/1     Running   0          2m16s
karmada-demo-metrics-adapter-68b67644dc-b7fmh           1/1     Running   0          2m16s
karmada-demo-metrics-adapter-68b67644dc-v9k5k           1/1     Running   0          2m16s
karmada-demo-scheduler-847795db5c-9thjs                 1/1     Running   0          2m16s
karmada-demo-webhook-766df78896-ccwkl                   1/1     Running   0          2m16s

➜  karmada git:(master) ✗ kubectl -n test  get karmada karmada-demo -o yaml | grep -C 10 'conditions'
      resources: {}
    kubeControllerManager:
      imageRepository: registry.k8s.io/kube-controller-manager
      imageTag: v1.25.4
      replicas: 1
      resources: {}
  hostCluster:
    networking:
      dnsDomain: cluster.local
status:
  conditions:
  - lastTransitionTime: "2023-11-06T11:40:52Z"
    message: karmada init job is completed
    reason: Completed
    status: "True"
    type: Ready
  secretRef:
    name: karmada-demo-admin-config
    namespace: test

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

`karmada-operator`: Fix karmada instance aggregated service externalName and namespace error.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (4ac2871) 52.83% compared to head (5fd5572) 52.84%.

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4210   +/-   ##
=======================================
  Coverage   52.83%   52.84%           
=======================================
  Files         239      239           
  Lines       23558    23558           
=======================================
+ Hits        12448    12450    +2     
+ Misses      10433    10432    -1     
+ Partials      677      676    -1     

Flag	Coverage Δ
unittests	52.84% <ø> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

see 2 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[wawa0210]

/reset e2e

[calvin0327]

/lgtm

@RainbowMango @jwcesign /cc

[jwcesign]

I think we need release notes:

`karmada-operator`: Fix karmada instance aggregated service externalName error.

[wawa0210]

I think we need release notes:

`karmada-operator`: Fix karmada instance aggregated service externalName error.

done

[XiShanYongYe-Chang]

Thanks~
LGTM

[jwcesign]

/lgtm

[RainbowMango]

/approve

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RainbowMango

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• operator/OWNERS [RainbowMango]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment