Update the Delegation logic for LookUp Call nodes (#2257)

Incorrect logic for determining whether a LookUp Call node could be
delegated was added in a previous PR
#2065

Updating the logic to ensure proper handling of edge cases

src/libraries/Microsoft.PowerFx.Core/Texl/Builtins/Lookup.cs

@@ -175,7 +175,7 @@ function is LookUpFunction lookup && args.Count > 2 &&
                 return false;
             }
 
-            return IsValidCallNodeInternal(node, binding, metadata, trackingFunction ?? Function);
+            return base.IsValidCallNode(node, binding, metadata, trackingFunction ?? Function);
         }
     }
 }