Remove EphemeralContainers feature gate from Kind config

- Ephemeral Containers have been promoted to GA as of Kubernetes 1.27
  and this feature gate has been removed
  See: kubernetes/kubernetes#111402
- Having it set prevents Kind clusters from starting successfully with
versions >= 1.27

Authored-by: Tim Downey <tdowney@vmware.com>

scripts/assets/kind-config.yaml

@@ -9,8 +9,6 @@ containerdConfigPatches:
     [plugins."io.containerd.grpc.v1.cri".registry.configs]
       [plugins."io.containerd.grpc.v1.cri".registry.configs."127.0.0.1:30050".tls]
         insecure_skip_verify = true
-featureGates:
-  EphemeralContainers: true
 nodes:
 - role: control-plane
   extraPortMappings: