Repository: flutter
Issue: [RFW] Loops are not working in widget builder scopes
Labels: package,team-ecosystem,has reproducible steps,P2,p: rfw,triaged-ecosystem,found in release: 3.27,found in release: 3.28

### Steps to reproduce

1. Create a local widget and provide a builderArg containing an array of texts (could be a map as well).
```
runtime.update(localLibraryName, LocalWidgetLibrary(<String, LocalWidgetBuilder> {
  'Builder': (context, source) {
    final args = {
      'values': ['Value1', 'Value2', 'Value3'],
    };
    return source.builder(['builder'], args);
  },
}));
```
2. Try to loop through the strings inside "values" in a ListView.
```
widget root = Builder(
  builder: (scope) => ListView(
    children: [
      ...for value in scope.values:
        Text(text: value, textDirection: 'ltr')
    ],
  ),
);
```

### Expected results

A ListView having 3 Text widgets with values "Value1", "Value2", "Value3" respectively should be rendered.


### Actual results

Nothing is rendered properly. Basically, the loop is ignored.

But, we can see the content when we use the array of values in a Text widget.
```
widget root = Builder(
  builder: (scope) => Text(text: scope.values, textDirection: 'ltr'),
);
```
The output of above is "Value1Value2Value3".

Is there anything that I miss to make loops work in widget builders or this is a legit issue?

<details><summary>Here's a full example</summary>
<p>

```
import 'package:flutter/material.dart';
import 'package:rfw/formats.dart' show parseLibraryFile;
import 'package:rfw/rfw.dart';

void main() {
  runApp(const Example());
}

class Example extends StatefulWidget {
  const Example({super.key});

  @override
  State<Example> createState() => _ExampleState();
}

class _ExampleState extends State<Example> {
  final Runtime _runtime = Runtime();
  final DynamicContent _data = DynamicContent();

  static const coreLibraryName = LibraryName(['core', 'widgets']);
  static const localLibraryName = LibraryName(['local', 'widgets']);
  static const remoteLibraryName = LibraryName(['remote']);

  static final RemoteWidgetLibrary _remoteWidgets = parseLibraryFile('''
    import core.widgets;
    import local.widgets;

    widget root = Builder(
      builder: (scope) => ListView(
        children: [
          ...for value in scope.values:
            Text(text: value, textDirection: 'ltr')
        ],
      ),
    );
''');
  static final WidgetLibrary _localWidgets =
      LocalWidgetLibrary(<String, LocalWidgetBuilder>{
    'Builder': (context, source) {
      final args = {
        'values': ['Value1', 'Value2', 'Value3'],
      };
      return source.builder(['builder'], args);
    },
  });

  @override
  void initState() {
    super.initState();
    // Core widget library
    _runtime.update(coreLibraryName, createCoreWidgets());
    // Local widget library
    _runtime.update(localLibraryName, _localWidgets);
    // Remote widget library
    _runtime.update(remoteLibraryName, _remoteWidgets);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(toolbarHeight: 0),
        body: RemoteWidget(
          runtime: _runtime,
          data: _data,
          widget: const FullyQualifiedWidgetName(
            remoteLibraryName,
            'root',
          ),
        ),
      ),
    );
  }
}
```

</p>
</details>