Investigate issue with getting etcdadmcluster object due to unknown namespace

[vivek-koppuru]

https://t.corp.amazon.com/P167063564

There are two issues called out:

1. The cache is not functioning properly, resulting in a null namespace. Logs have been attached for reference.
2. Cluster certificates were updated, but the etcdadmcontroller pod continued reporting them as invalid.
   The log error message itself is clear and includes valid dates, yet the pod still flagged the certificates as invalid. This caused the kube-apiserver to become non-responsive for a period.

We need to figure out how to get rid of the specific errors from the first part and figure our why restarting the pods would cause the certificate to be counted.