feat(feed_decorators): implement dynamic height for dismissed widget

Refactors `DecoratorDismissedWidget` to have a dynamic height that mirrors the user's selected headline tile style.

- The widget now reads `headlineImageStyle` from the `AppBloc` state.
- A helper method calculates the appropriate height based on the user's setting, ensuring a seamless UI transition when a decorator is dismissed by preventing layout jank.
- This change addresses the issue of the widget having a fixed, hardcoded height.

Author: fulleni

lib/feed_decorators/widgets/decorator_dismissed_widget.dart

@@ -1,30 +1,55 @@
+import 'package:core/core.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:flutter_news_app_mobile_client_full_source_code/app/bloc/app_bloc.dart';
 import 'package:flutter_news_app_mobile_client_full_source_code/l10n/l10n.dart';
 import 'package:ui_kit/ui_kit.dart';
 
 /// {@template decorator_dismissed_widget}
 /// A widget displayed in place of a feed decorator after it has been
 /// dismissed by the user.
+///
+/// This widget's height dynamically adjusts to match the user's selected
+/// headline tile style to prevent layout shifts in the feed.
 /// {@endtemplate}
 class DecoratorDismissedWidget extends StatelessWidget {
   /// {@macro decorator_dismissed_widget}
   const DecoratorDismissedWidget({super.key});
 
+  /// Determines the height of the widget based on the user's feed preference.
+  ///
+  /// This ensures that when a decorator is dismissed, the placeholder that
+  /// replaces it has a similar height to the surrounding headline tiles,
+  /// preventing a jarring layout shift.
+  double _getDynamicHeight(HeadlineImageStyle imageStyle) {
+    return switch (imageStyle) {
+      // Approximate height for a text-only list tile.
+      HeadlineImageStyle.hidden => 80,
+      // Approximate height for a list tile with a leading image.
+      HeadlineImageStyle.smallThumbnail => 100,
+      // Approximate height for a card with an image on top.
+      HeadlineImageStyle.largeThumbnail => 280,
+    };
+  }
+
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
     final l10n = AppLocalizationsX(context).l10n;
+    final headlineImageStyle = context
+        .watch<AppBloc>()
+        .state
+        .headlineImageStyle;
 
     return Card(
       margin: const EdgeInsets.symmetric(
         horizontal: AppSpacing.lg,
         vertical: AppSpacing.md,
       ),
-      // TODO(fulleni): size must reflect the hight of the selected headlines feed tile widget.
       child: SizedBox(
-        // This height is an approximation of the CallToActionDecoratorWidget's
-        // height to ensure minimal layout shift upon dismissal.
-        height: 140,
+        // The height is dynamically set to match the current headline tile
+        // style, ensuring a smooth visual transition upon dismissal.
+        height: _getDynamicHeight(headlineImageStyle),
         child: Center(
           child: Text(
             l10n.decoratorDismissedConfirmation,