isRegisteredIn method
Checks whether this store is registered in scope.
Returns true when registration metadata exists, even if not instantiated.
Implementation
bool isRegisteredIn(LevitScope scope, {String? tag}) {
final instanceKey =
tag != null ? 'ls_store_${_getStoreTag(this, tag)}' : _defaultKey;
return scope.isRegistered<_LevitStoreInstance<T>>(tag: instanceKey);
}