Duplicate Key Entry for kube-apiserver is not allowed during upgrade(In which the keys are used for pod-identity)

**We have set up the POD-IDENTITY on the self-hosted cluster, and we are adding the flags to kube-apiserver, which is required for pod-identity, but whenever we upgrade the cluster, the kube-apiserver is not allowing the duplicate keys**;

- --service-account-issuer=https://s3.us-east-2.amazonaws.com/wyyezswwshyxpegianfnorveydsmotak
- --service-account-issuer=https://kubernetes.default.svc.cluster.local/
- --service-account-key-file=/etc/kubernetes/pki/sa.pub
- --service-account-key-file=/etc/kubernetes/pki/sa-pkcs8.pub

In the above mentioned keys `- --service-account-issuer=https://s3.us-east-2.amazonaws.com/wyyezswwshyxpegianfnorveydsmotak` and `- --service-account-key-file=/etc/kubernetes/pki/sa-pkcs8.pub` are getting removed whenever we upgrade the the kube-apiserver

After the upgrade, we can re-add duplicate entries, but we need these entries to be supported during the upgrade process as well.

**What you expected to happen**:
Whenever we upgrade the kube-apiserver, we should not see this kind of behavior.

Start by reproducing the kube-apiserver upgrade with the listed service-account-issuer and service-account-key-file flags, then trace how the upgrade handles duplicate entries. Done means both issuer values and both key-file values remain supported through the upgrade without manual re-addition.

Written by the indexing model from the issue text.