vSphere Username and Password Changes

**What happened**: When creating a workload cluster and using different credentials than what the management cluster was created with, the workload cluster is created and we can see on the management cluster that the credentials are as expected. After a few mins, we check the secret again for the credentials and they are changed to match what is used to create the management cluster.

**What you expected to happen**: We would expect that each cluster could have it's own credentials and not what the management cluster uses.

**How to reproduce it (as minimally and precisely as possible)**: Create a management cluster. Change to different credentials. Create workload cluster via the management cluster.

**Anything else we need to know?**: Trying to verify how to use a single management cluster to provision workload clusters in multiple vsphere servers/datacenters. Seems like we would have to use the same credentials across the board?

**Environment**:
- EKS Anywhere Release: v0.11.4
- EKS Distro Release: kubernetes-1-23-eks-5, kubernetes-1-23-eks-8

Reproduce the v0.11.4 scenario by creating a management cluster, changing the vSphere credentials, and provisioning a workload cluster from it. Trace the management-cluster secret and workload-cluster provisioning flow, then verify that workload credentials remain distinct and are not changed back to the management cluster credentials.

Written by the indexing model from the issue text.