Install iptables rules to allow AntreaProxy health check packets

[hongliangl]

No description provided.

[luolanzone]

LGTM overall, one nit.

[hongliangl]

/test-all

[luolanzone]

I noticed that !serviceHealthServerDisabled was also checked in #7371, it seems we also need to check it as well before install the rules?

[hongliangl]

We don't need to check that, in cmd/antrea-agent.go:

	var proxyHealthCheckPort int
	if !o.config.AntreaProxy.DisableServiceHealthCheckServer {
		_, proxyHealthCheckPortStr, _ := net.SplitHostPort(o.config.AntreaProxy.ServiceHealthCheckServerBindAddress)
		proxyHealthCheckPort, _ = strconv.Atoi(proxyHealthCheckPortStr)
	}