Cilium's init containers run as UID 0 with capabilities (including
CAP_DAC_OVERRIDE) dropped, so host paths it writes to (e.g. /opt/cni/bin)
must be owned by root or it will fail with a permission error.
Add a pre-flight assert that fails fast with a clear message when
kube_network_plugin == cilium and kube_owner != root, instead of
changing CNI bin ownership defaults for all network plugins.