bgpd: Don't set `non-transitive` for extcommunity bandwidth by default

bgpd: Don't set `non-transitive` for extcommunity bandwidth by default

Before:

```
~/frr# vtysh -c 'conf' -c 'route-map testas permit 10' -c 'set extcommunity bandwidth 321'
~/frr# vtysh -c 'show route-map testas' | grep 321
    extcommunity bandwidth 321 non-transitive
~/frr# vtysh -c 'show run' | grep 321
 set extcommunity bandwidth 321 non-transitive
```

After:

```
~/frr# vtysh -c 'conf' -c 'route-map testas permit 10' -c 'set extcommunity bandwidth 321'
~/frr# vtysh -c 'show route-map testas' | grep 321
    extcommunity bandwidth 321
~/frr# vtysh -c 'show run' | grep 321
 set extcommunity bandwidth 321
~/frr# vtysh -c 'conf' -c 'route-map testas permit 20' -c 'set extcommunity bandwidth 321 non-tra'
~/frr# vtysh -c 'show run' | grep 321
 set extcommunity bandwidth 321
 set extcommunity bandwidth 321 non-transitive
```

Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>