Description of problem:

When accepting a managed cluster on the hub, if the cluster namespace is in the terminating state for some reason, the request should be denied.

There are two cases in this situation:
Case 1: The ManagedCluster CR has been created with spec.hubAcceptsClient: false. The update request for this ManagedCluster to change spec.hubAcceptsClient to true should be denied;

Case 2: The request to create a ManagedCluster CR with spec.hubAcceptsClient: true should be denied;

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

  How reproducible:

  Steps to Reproduce:

1.  
2.  
3. ...

Actual results:

Expected results:

Additional info: