Description of problem:

Customer attempted to upgrade ACM from 2.11 > 2.12 but this failed due to an unknown reason. In an attempt to recover they attempted an uninstall reinstall leaving MCH in uninstalling state and MCE in error. 

Attempting to manually work through the uninstall process led to this error when trying to detach the managed clusters:

oc delete managedcluster cluster-qa Error from server (InternalError): Internal error occurred: failed calling webhook "ocm.validating.webhook.admission.open-cluster-management.io": failed to call webhook: Post "https://ocm-webhook.multicluster-engine.svc:443/validating?timeout=10s": no endpoints available for service "ocm-webhook"

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

2.11/2.12

How reproducible:

Not sure, only seen this once

Steps to Reproduce:

1. Start with a broken upgrade from 2.11 to 2.12
2. attempt to uninstall mch
3. ...

Actual results:

MCH stuck uninstalling and MCE in error

Expected results:

Uninstall is successful

Additional info: