Service router-advert failed to start radvd with more then
To reproduce:
```
set service router-advert interface eth1 default-preference 'high'
set service router-advert interface eth1 hop-limit '64'
set service router-advert interface eth1 name-server '2001:db8:1111::1'
set service router-advert interface eth1 name-server '2001:db8:1111::2'
set service router-advert interface eth1 name-server '2001:db8:1111::3'
set service router-advert interface eth1 name-server '2001:db8:1111::4'
set service router-advert interface eth1 no-send-advert
set service router-advert interface eth1 prefix 2001:db8::/64
commit
```
Logs:
```
vyos@r14# sudo journalctl -u radvd
May 24 12:04:42 r14 systemd[1]: Stopping radvd.service - Router advertisement daemon for IPv6...
May 24 12:04:42 r14 systemd[1]: radvd.service: Deactivated successfully.
May 24 12:04:42 r14 systemd[1]: Stopped radvd.service - Router advertisement daemon for IPv6.
May 24 12:04:47 r14 systemd[1]: Starting radvd.service - Router advertisement daemon for IPv6...
May 24 12:04:47 r14 radvd[131995]: too many addresses in RDNSS section
May 24 12:04:47 r14 radvd[131995]: exiting, failed to read config file
May 24 12:04:47 r14 systemd[1]: radvd.service: Control process exited, code=exited, status=1/FAILURE
May 24 12:04:47 r14 systemd[1]: radvd.service: Failed with result 'exit-code'.
May 24 12:04:47 r14 systemd[1]: Failed to start radvd.service - Router advertisement daemon for IPv6.
[edit]
vyos@r14#
```
Status
```
vyos@r14# sudo systemctl status radvd
× radvd.service - Router advertisement daemon for IPv6
Loaded: loaded (/lib/systemd/system/radvd.service; disabled; preset: enabled)
Drop-In: /etc/systemd/system/radvd.service.d
└─override.conf
Active: failed (Result: exit-code) since Wed 2023-05-24 12:04:47 EEST; 7s ago
Docs: man:radvd(8)
Process: 131995 ExecStartPre=/usr/sbin/radvd --logmethod stderr_clean --configtest --config /run/radvd/radvd.conf (code=exited, status=1/FAILURE)
CPU: 11ms
May 24 12:04:47 r14 systemd[1]: Starting radvd.service - Router advertisement daemon for IPv6...
May 24 12:04:47 r14 radvd[131995]: too many addresses in RDNSS section
May 24 12:04:47 r14 radvd[131995]: exiting, failed to read config file
May 24 12:04:47 r14 systemd[1]: radvd.service: Control process exited, code=exited, status=1/FAILURE
May 24 12:04:47 r14 systemd[1]: radvd.service: Failed with result 'exit-code'.
May 24 12:04:47 r14 systemd[1]: Failed to start radvd.service - Router advertisement daemon for IPv6.
[edit]
vyos@r14#
```
This bug with radvd described here https://github.com/radvd-project/radvd/issues/182