fix(ast): action AddListItem() should accept "default" as parameter

AddListItem() was incorrectly set to accept no positional
parameters, but it should be accepting "default" as an optional
positional parameter to set the default value of a dropdown menu
list.

src/engine/ast.ts

@@ -2065,7 +2065,7 @@ export class OvaleASTClass {
             tokenStream,
             "ParseAddListItem",
             annotation,
-            0,
+            1,
             checkListItemParameters
         );
         if (!positionalParams || !namedParams) return undefined;