How can we add a widget snapshot or placeholder like in the "Widget Galley" list as I have marked in red below? Once I create a widget I can see my app available under the list however not able to make it appear as a snapshot or image. Any help will be appreciated. `private struct ToDoLockScreenWidgetView : View {   var entry: Provider.Entry   @Environment(.widgetFamily) var family       var body: some View {     if #available(iOSApplicationExtension 16.0, *) {       ZStack {         AccessoryWidgetBackground()         Text(entry.toDoWidget?.title ?? "Not available")           .multilineTextAlignment(.center)           .font(.subheadline)           .widgetAccentable()       }       .previewContext(WidgetPreviewContext(family: .accessoryCircular))       .previewDisplayName("(family)")     } else {       Text("")     }   } }