graph/db: let ForEachNodeCached maybe fetch node addresses

Here we adjust the ForEachNodeCached graph DB method to pass in a node's
addresses into the provided call-back if requested. This will allow us
to improve the performance of node/channel iteration in the autopilot
subserver.

rpcserver.go

@@ -7183,7 +7183,8 @@ func (r *rpcServer) GetNetworkInfo(ctx context.Context,
 	// network, tallying up the total number of nodes, and also gathering
 	// each node so we can measure the graph diameter and degree stats
 	// below.
-	err := graph.ForEachNodeCached(ctx, func(node route.Vertex,
+	err := graph.ForEachNodeCached(ctx, false, func(ctx context.Context,
+		node route.Vertex, _ []net.Addr,
 		edges map[uint64]*graphdb.DirectedChannel) error {
 
 		// Increment the total number of nodes with each iteration.