Fixed nested List fromJson

bin/tdlib_gen.dart

@@ -174,6 +174,7 @@ String findFromJsonHandling(
   String functionPrefix = 'f.',
   String? varNameInsteadOfKeyName}
   ) {
+  final varAccess = varNameInsteadOfKeyName ?? "json['$keyName']";
   if (type.startsWith('vector<')) {
     final tmp1 = type.replaceFirst('vector<', '');
     final tmp2 = tmp1.substring(0, tmp1.length - 1);
@@ -187,10 +188,9 @@ String findFromJsonHandling(
       objectPrefix: objectPrefix,
       varNameInsteadOfKeyName: 'e',
     );
-    return "(json['$keyName'] as List<dynamic>).map((e) => ($innerHandler)).toList(growable: false)";
+    return '($varAccess as List<dynamic>).map((e) => ($innerHandler)).toList(growable: false)';
   }
 
-  final varAccess = varNameInsteadOfKeyName ?? "json['$keyName']";
   final predefined = {
     'double': 'double',
     'string': 'String',