Update getters style

lib/src/core/model/dependencies_storage.dart

@@ -3,9 +3,9 @@ import 'package:purple_starter/src/core/database/drift/app_database.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 abstract class IDependenciesStorage {
-  Dio get dio;
-  AppDatabase get database;
-  SharedPreferences get sharedPreferences;
+  abstract final Dio dio;
+  abstract final AppDatabase database;
+  abstract final SharedPreferences sharedPreferences;
 
   void close();
 }

lib/src/core/model/repository_storage.dart

@@ -4,7 +4,7 @@ import 'package:purple_starter/src/feature/settings/repository/settings_reposito
 import 'package:shared_preferences/shared_preferences.dart';
 
 abstract class IRepositoryStorage {
-  ISettingsRepository get settings;
+  abstract final ISettingsRepository settings;
 }
 
 class RepositoryStorage implements IRepositoryStorage {

lib/src/feature/settings/database/settings_dao.dart

@@ -2,7 +2,7 @@ import 'package:purple_starter/src/core/database/shared_preferences/shared_prefe
 import 'package:shared_preferences/shared_preferences.dart';
 
 abstract class ISettingsDao {
-  String? get themeMode;
+  abstract final String? themeMode;
   Future<void> setThemeMode(String value);
 }
 

lib/src/feature/settings/repository/settings_repository.dart

@@ -4,7 +4,7 @@ import 'package:purple_starter/src/feature/settings/database/settings_dao.dart';
 import 'package:purple_starter/src/feature/settings/enum/app_theme.dart';
 
 abstract class ISettingsRepository {
-  AppTheme? get theme;
+  abstract final AppTheme? theme;
   Future<void> setTheme(AppTheme value);
 }