fetchItems method
Implementation
Future<void> fetchItems() async {
final stringItems = await Utils().getPrefsString(key: ITEMS_PREF_KEY);
if (stringItems == null) return;
final jsonItems = jsonDecode(stringItems);
items = List<ATHMovilItem>.from(
jsonItems.map((item) => ATHMovilItem.fromMap(item)),
);
notifyListeners();
}