DevTools "Count widget builds" only works in debug mode, not in --profile mode

### Steps to reproduce

1. flutter run --profile --track-widget-creation
2. Open DevTools → Performance
3. The "Count widget builds" checkbox is greyed out.

### Expected results

The flag name `--track-widget-creation` suggests this should still be
available in profile mode. Documentation should clarify that widget build tracking is available debug-only.

### Actual results

I could not check the box to display the widget rebuilds, and the tooltip was not any help either. Documentation never mentions this. AI doesn't know.

### Code sample

Code sample

```dart
[Paste your code here]
```

### Screenshots or Video

Screenshots / Video demonstration

[Upload media here]

### Logs

Logs

```console
[Paste your logs here]
```

### Flutter Doctor output

Doctor output

```console
[Paste your output here]
```

Commencez par la documentation de --track-widget-creation et le contrôle « Count widget builds » de la page DevTools Performance, en utilisant `flutter run --profile --track-widget-creation` pour reproduire la case à cocher désactivée. C’est terminé lorsque la documentation et l’infobulle indiquent clairement que le suivi de la construction des widgets est disponible uniquement en mode debug, y compris le comportement en mode profile.

Rédigé par le modèle d'indexation à partir du texte de l'issue.