Added a check that we have a route before attempting to include it in the other URLs for a published document. (#18135)

src/Umbraco.Core/Routing/NewDefaultUrlProvider.cs

@@ -117,7 +117,7 @@ public class NewDefaultUrlProvider : IUrlProvider
 
             // although we are passing in culture here, if any node in this path is invariant, it ignores the culture anyways so this is ok
             var route = GetLegacyRouteFormatById(key, culture);
-            if (route == null)
+            if (route == null || route == "#")
             {
                 continue;
             }