Ensure namespace is proxied to grpc/ttrpc plugins

Before this change we only ever had the grpc incoming medata set so when
we make a request to a shim or a grpc plugin the namespace is not sent
over the RPC.

I need this for github.com/cpuguy83/systemdshim, and I am sure there are
other use-cases where this would be needed.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

services/server/server.go

@@ -102,10 +102,12 @@ func New(ctx context.Context, config *srvconfig.Config) (*Server, error) {
 		grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(
 			otelgrpc.StreamServerInterceptor(),
 			grpc.StreamServerInterceptor(grpc_prometheus.StreamServerInterceptor),
+			streamNamespaceInterceptor,
 		)),
 		grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(
 			otelgrpc.UnaryServerInterceptor(),
 			grpc.UnaryServerInterceptor(grpc_prometheus.UnaryServerInterceptor),
+			unaryNamespaceInterceptor,
 		)),
 	}
 	if config.GRPC.MaxRecvMsgSize > 0 {