Description of problem:

On a MDR setup, While trying to deploy application set based application from ACM console, UI throws an error in placement page saying  "ClusterSets failed to load. Check the GitOpsCluster and Placement YAML for status errors."

The  same issue was reported in  https://issues.redhat.com/browse/ACM-6066 and now not working in the latest 2.9.0 in MDR.

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

2.9.0

Snapshot- 
2.9.0-DOWNSTREAM-2023-10-24-21-34-08

How reproducible:

Always

Steps to Reproduce:

1. Go to All Clusters -> Applications -> Create application -> Application set
2. Provide details required from steps 1 to 3 and reach step 4 "Placement" page
3. Observe the error "ClusterSets failed to load. Check the GitOpsCluster and Placement YAML for status errors."

Actual results:

UI throws error "ClusterSets failed to load. Check the GitOpsCluster and Placement YAML for status errors." and does not allow to select any clusterset.

Expected results:

There should not be any error while creating application set based applications

Additional info:

GitOpsCluster and Placement YAML output from the cluster:
```
$ oc get gitopscluster gitops-cluster -n openshift-gitops -oyaml
apiVersion: apps.open-cluster-management.io/v1beta1
kind: GitOpsCluster
metadata:
  creationTimestamp: "2023-10-25T12:19:33Z"
  generation: 1
  name: gitops-cluster
  namespace: openshift-gitops
  resourceVersion: "13707462"
  uid: a1e99423-a860-4a77-8d2a-7abe1a4c229f
spec:
  argoServer:
    argoNamespace: openshift-gitops
    cluster: local-cluster
  placementRef:
    apiVersion: cluster.open-cluster-management.io/v1beta1
    kind: Placement
    name: all-openshift-clusters
    namespace: openshift-gitops
status:
  lastUpdateTime: "2023-11-02T07:46:23Z"
  message: Added managed clusters [local-cluster pbyregow-mc1 pbyregow-mc2] to gitops
    namespace openshift-gitops
  phase: successful```
 
```$ oc get placement -A
NAMESPACE          NAME                           SUCCEEDED   REASON                  SELECTEDCLUSTERS
b-sub-1            b-sub-1-placement-1            True        AllDecisionsScheduled   1
b-sub-2            b-sub-2-placement-1            True        AllDecisionsScheduled   1
b-sub-3            b-sub-3-placement-1            True        AllDecisionsScheduled   1
b-sub-4            b-sub-4-placement-1            True        AllDecisionsScheduled   1
cronjob-sub-1      cronjob-sub-1-placement-1      True        AllDecisionsScheduled   1
cronjob-sub-2      cronjob-sub-2-placement-1      True        AllDecisionsScheduled   1
job-sub-1          job-sub-1-placement-1          True        AllDecisionsScheduled   1
job-sub-2          job-sub-2-placement-1          True        AllDecisionsScheduled   1
logwritter-sub-1   logwritter-sub-1-placement-1   True        AllDecisionsScheduled   1
logwritter-sub-2   logwritter-sub-2-placement-1   True        AllDecisionsScheduled   1
new-sub-1          new-sub-1-placement-1          True        AllDecisionsScheduled   1
new-sub-2          new-sub-2-placement-1          True        AllDecisionsScheduled   1
openshift-gitops   all-openshift-clusters         True        AllDecisionsScheduled   3
openshift-gitops   busybox-1-placement            True        AllDecisionsScheduled   1
openshift-gitops   busybox-2-placement            True        AllDecisionsScheduled   1
openshift-gitops   busybox-3-placement            True        AllDecisionsScheduled   1
openshift-gitops   busybox-4-placement            True        AllDecisionsScheduled   1
openshift-gitops   cronjob-1-placement            True        AllDecisionsScheduled   1
openshift-gitops   cronjob-2-placement            True        AllDecisionsScheduled   1
openshift-gitops   j-1-placement                  True        AllDecisionsScheduled   1
openshift-gitops   j-2-placement                  True        AllDecisionsScheduled   1
openshift-gitops   logwriter-app-1-placement      True        AllDecisionsScheduled   1
openshift-gitops   logwriter-app-2-placement      True        AllDecisionsScheduled   1
openshift-gitops   new-app-1-placement            True        AllDecisionsScheduled   1
openshift-gitops   new-app-2-placement            True        AllDecisionsScheduled   1```