add kernel version check for `kubeadm upgrade`

[pacoxu]

Currently, only root check and corefile migration check before upgrading node.

// RunRootCheckOnly initializes checks slice of structs and call RunChecks
func RunRootCheckOnly(ignorePreflightErrors sets.Set[string]) error {
	checks := []Checker{
		IsPrivilegedUserCheck{},
	}

	return RunChecks(checks, os.Stderr, ignorePreflightErrors)
}

xref https://github.com/kubernetes/kubernetes/issues/102612#issuecomment-2367145050

• For new clusters: In system-validator, https://github.com/kubernetes/system-validators/pull/37 was merged recently.
• For upgrades, I think there is no kernel version check there. I need to verify to see if we need to add a warning for upgrading.