Description of problem:

Cannot modify hubAcceptsClient to false if auto-approval is enabled

Version-Release number of selected component (if applicable): ACM 2.12.0

How reproducible:

Steps to Reproduce:

1. Enable auto-approval in cluster manager
2. Import a managed cluster. the managed cluster join request is auto-approved and accepted.
3. modify the hubAcceptsClient to false, it is reset to true

Actual results:

Expected results:

set hubAcceptsClient to false if the cluster is already joined and available. the auto-approval should not impact on the existing managed cluster.

Additional info: