graph/db: add version parameter to IsPublicNode

Make IsPublicNode version-aware by routing to the appropriate SQL
query based on gossip version. V1 and v2 have different criteria for
determining node publicity (v1 requires four signatures, v2 requires
one). Convert TestNodeIsPublic to versioned test for both protocols.

graph/db/graph.go

@@ -637,7 +637,7 @@ func (c *ChannelGraph) HasV1Node(ctx context.Context,
 
 // IsPublicNode determines whether the node is seen as public in the graph.
 func (c *ChannelGraph) IsPublicNode(pubKey [33]byte) (bool, error) {
-	return c.db.IsPublicNode(pubKey)
+	return c.db.IsPublicNode(lnwire.GossipVersion1, pubKey)
 }
 
 // ForEachChannel iterates through all channel edges stored within the graph.
@@ -861,6 +861,11 @@ func (c *VersionedGraph) DeleteChannelEdges(strictZombiePruning,
 	return err
 }
 
+// IsPublicNode determines whether the node is seen as public in the graph.
+func (c *VersionedGraph) IsPublicNode(pubKey [33]byte) (bool, error) {
+	return c.db.IsPublicNode(c.v, pubKey)
+}
+
 // MakeTestGraph creates a new instance of the ChannelGraph for testing
 // purposes. The backing Store implementation depends on the version of
 // NewTestDB included in the current build.