graph: remove one context.TODO

By threading a context through to the Builder's ForAllOutgoingChannels
method.

graph/builder.go

@@ -1275,10 +1275,9 @@ func (b *Builder) FetchLightningNode(ctx context.Context,
 // the router.
 //
 // NOTE: This method is part of the ChannelGraphSource interface.
-func (b *Builder) ForAllOutgoingChannels(cb func(*models.ChannelEdgeInfo,
-	*models.ChannelEdgePolicy) error) error {
-
-	ctx := context.TODO()
+func (b *Builder) ForAllOutgoingChannels(ctx context.Context,
+	cb func(*models.ChannelEdgeInfo,
+		*models.ChannelEdgePolicy) error) error {
 
 	return b.cfg.Graph.ForEachNodeChannel(ctx, b.cfg.SelfNode,
 		func(c *models.ChannelEdgeInfo, e *models.ChannelEdgePolicy,