feat(server/v2/cometbft): config (#20989)

server/v2/api/grpcgateway/server.go

@@ -84,7 +84,7 @@ func (s *GRPCGatewayServer[T]) Config() any {
 func (s *GRPCGatewayServer[T]) Init(appI serverv2.AppI[transaction.Tx], v *viper.Viper, logger log.Logger) error {
 	cfg := s.Config().(*Config)
 	if v != nil {
-		if err := v.Sub(s.Name()).Unmarshal(&cfg); err != nil {
+		if err := serverv2.UnmarshalSubConfig(v, s.Name(), &cfg); err != nil {
 			return fmt.Errorf("failed to unmarshal config: %w", err)
 		}
 	}