lnwire+feature: add awareness of option_shutdown_anysegwit

In this commit, we add awareness of the option_shutdown_anysegwit that
permits both sides to send newer segwit based addresses. This'll
eventually enable us to send taproot addresses for co-op close.

feature/default_sets.go

@@ -79,4 +79,8 @@ var defaultSetDesc = setDesc{
 		SetInit:    {}, // I
 		SetNodeAnn: {}, // N
 	},
+	lnwire.ShutdownAnySegwitOptional: {
+		SetInit:    {}, // I
+		SetNodeAnn: {}, // N
+	},
 }