Switch cloud providers on Kubernetes cluster creation

With #22392 (closed), we are adding AWS EKS as a provider for Kubernetes integrations. When a user clicks which provider they want, they proceed to authentication, and then the cluster form.

On the cluster form, there is no way to go back to select a different provider. We should provide this capability.

Proposal

As cluster is created, leave provider buttons visible on top so that user can switch providers if desired.

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