Description of problem:

velero namespace stuck in 'Terminating' state if restores were created and executed

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

OADP 1.3 although it could have been reproducible in previous releases

How reproducible:

Always

Steps to Reproduce:
1. Create a set of velero restore resources
2. Delete the velero namespace  >> the namespaces is stuck in Terminating state
3.

Actual results:

Expected results:

Additional info:

This was reproduced with ACM , when the ACM backup component was disabled after a restore operation ( when the ACM backup component is disabled, OADP is uninstalled and the namespace where OADP was installed is deleted ). The ns name is open-cluster-management-backup

#oc get ns | grep Term
open-cluster-management-backup                     Terminating   9m3s

#oc describe ns open-cluster-management-backup
Name:         open-cluster-management-backup
Labels:       kubernetes.io/metadata.name=open-cluster-management-backup
              pod-security.kubernetes.io/audit=privileged
              pod-security.kubernetes.io/audit-version=v1.24
              pod-security.kubernetes.io/enforce=privileged
              pod-security.kubernetes.io/warn=privileged
              pod-security.kubernetes.io/warn-version=v1.24
Annotations:  openshift.io/sa.scc.mcs: s0:c38,c37
              openshift.io/sa.scc.supplemental-groups: 1001480000/10000
              openshift.io/sa.scc.uid-range: 1001480000/10000
Status:       Terminating
Conditions:
  Type                                         Status  LastTransitionTime               Reason                Message
  ----                                         ------  ------------------               ------                -------
  NamespaceDeletionDiscoveryFailure            False   Tue, 05 Mar 2024 17:18:00 -0500  ResourcesDiscovered   All resources successfully discovered
  NamespaceDeletionGroupVersionParsingFailure  False   Tue, 05 Mar 2024 17:18:00 -0500  ParsedGroupVersions   All legacy kube types successfully parsed
  NamespaceDeletionContentFailure              False   Tue, 05 Mar 2024 17:18:00 -0500  ContentDeleted        All content successfully deleted, may be waiting on finalization
  NamespaceContentRemaining                    True    Tue, 05 Mar 2024 17:18:00 -0500  SomeResourcesRemain   Some resources are remaining: restores.velero.io has 6 resource instances
  NamespaceFinalizersRemaining                 True    Tue, 05 Mar 2024 17:18:00 -0500  SomeFinalizersRemain  Some content in the namespace has finalizers remaining: restores.velero.io/external-resources-finalizer in 6 resource instances

#oc get restore.velero -A
NAMESPACE                        NAME                                                                      AGE
open-cluster-management-backup   rt-latest-passive-acm-credentials-schedule-20240305211330                 6m52s
open-cluster-management-backup   rt-latest-passive-acm-resources-generic-schedule-20240305211330           6m52s
open-cluster-management-backup   rt-latest-passive-acm-resources-schedule-20240305211330                   6m52s
open-cluster-management-backup   rt-with-timestamp-passive-acm-credentials-schedule-20240305210930         7m23s
open-cluster-management-backup   rt-with-timestamp-passive-acm-resources-generic-schedule-20240305210930   7m23s
open-cluster-management-backup   rt-with-timestamp-passive-acm-resources-schedule-20240305210930           7m23s