refactor: Update quick actions description and enhance AppCustomizationPage layout

- Revised the quick actions description in multiple languages to clarify their purpose as "Quickpills in chat."
- Adjusted the layout of AppCustomizationPage by reintroducing the quick pills section for improved user interaction.
- Modified spacing between UI elements for better visual consistency and usability.
- Streamlined the component structure to enhance maintainability and readability.

lib/l10n/app_localizations_fr.dart

@@ -889,8 +889,7 @@ class AppLocalizationsFr extends AppLocalizations {
   String get appCustomizationSubtitle => 'Thème, langue, voix et quickpills';
 
   @override
-  String get quickActionsDescription =>
-      'Choisissez jusqu\'à deux raccourcis à épingler près du champ de saisie';
+  String get quickActionsDescription => 'Raccourcis dans le chat';
 
   @override
   String get chatSettings => 'Discussion';