Actually validate network connectivity on NM MM setup

Ticket: https://progress.opensuse.org/issues/155278

lib/mm_network.pm

@@ -8,6 +8,7 @@ use Exporter;
 
 use testapi;
 use version_utils 'is_opensuse';
+use utils qw(validate_script_output_retry);
 
 our @EXPORT = qw(configure_hostname get_host_resolv_conf is_networkmanager restart_networking
   configure_static_ip configure_dhcp configure_default_gateway configure_static_dns
@@ -237,7 +238,7 @@ sub restart_networking {
         assert_script_run 'nmcli networking off';
         assert_script_run 'nmcli networking on';
         # Wait until the connections are configured
-        assert_script_run 'nmcli networking connectivity check';
+        validate_script_output_retry('nmcli networking connectivity check', m/full/, delay => 3, retry => 5);
     } else {
         assert_script_run 'rcnetwork restart';
     }