deleteAll method
Implementation
Future<void> deleteAll() async {
final keys = _prefs.getKeys()
.where((key) => key.startsWith(StorageConfig.prefsPrefix) &&
!key.contains(StorageConfig.imagePrefix))
.toList();
for (var key in keys) {
await _prefs.remove(key);
final cleanKey = key.replaceFirst(StorageConfig.prefsPrefix, '');
_updateSubject.add(cleanKey);
}
_dataSubject.add({});
}