[BGP] Nexthop 0.0.0.0 is treated as invalid nexthop in FRR 10.0.1, whereas in FRR8.5.4, it was a valid nexthop

[BGP] Nexthop 0.0.0.0 is treated as invalid nexthop in FRR 10.0.1, whereas in FRR8.5.4, it was a valid nexthop #25647