Description of problem:

When the user tries to uninstall ACM, MCE will fail to uninstall due to the `cluster-manager` component failing to be removed:

status:
  conditions:
    - lastTransitionTime: '2023-09-11T17:05:22Z'
      lastUpdateTime: '2023-09-11T17:05:22Z'
      reason: ComponentsUnavailable
      status: 'False'
      type: Available
    - lastTransitionTime: '2023-09-11T19:53:22Z'
      lastUpdateTime: '2023-09-11T19:53:22Z'
      message: ClusterManager cluster-manager still exists.
      reason: WaitingForResource
      status: 'False'
      type: Progressing

When diving deeper into the issue, the `cluster-manager` component is failing due to a ManagedClusterSet CR remaining within the cluster:

E0911 19:49:53.913881 1 base_controller.go:270] "ClusterManagerController" controller failed to sync "cluster-manager", err: Thera are still reaming CRDs: managedclustersets.cluster.open-cluster-management.io

After checking the CR that is remaining within the cluster, we have determined that the issue is being caused by the `submariner-addon` finalizer preventing the resource from being deleted:

apiVersion: cluster.open-cluster-management.io/v1beta2
kind: ManagedClusterSet
metadata:
  annotations:
    cluster.open-cluster-management.io/submariner-broker-ns: default-broker
  deletionTimestamp: '2023-09-12T13:54:22Z'
  resourceVersion: '332057'
  name: default
  uid: f9e5b8ee-351e-4f41-a5f6-3eb083b49257
  deletionGracePeriodSeconds: 0
  creationTimestamp: '2023-09-12T13:44:21Z'
  finalizers:
    - cluster.open-cluster-management.io/submariner-cleanup
spec:
  clusterSelector:
    selectorType: ExclusiveClusterSetLabel
status:
  conditions:
    - lastTransitionTime: '2023-09-12T13:44:26Z'
      message: 1 ManagedClusters selected
      reason: ClustersSelected
      status: 'False'
      type: ClusterSetEmpty 

From discussions with skitt@redhat.com, the `submariner-addon` finalizer should not be added to the `default` ManagedClusterSet. By removing the finalizer, the uninstall is able to proceed and finish as expected. We need to ensure that the finalizer is not added by the `submariner-addon` to this ManagedClusterSet, since the addon is removed before the finalizer is able to be removed upon uninstall.

Version-Release number of selected component (if applicable):

ACM 2.9.0 / MCE 2.4.0

How reproducible:

Always

Steps to Reproduce:

1. Deploy ACM 2.9.0 build
2. Uninstall the operator from the Installed Operator page on the OCP console.
3. Wait until MCE is being uninstalled, MCE will progress to the stage where it is blocked from uninstall due to `cluster-manager`.
4. Check the `default` ManagedClusterSet and see that the `submariner-addon` finalizer is set and preventing it from being removed.

Actual results:

ACM / MCE is prevented from being uninstalled from the cluster environment.

Expected results:

Uninstall proceeds without being stalled by ManagedClusterSet resource.

Additional info: