clear method
Removes all the conversation listeners for the given chat.
Implementation
Future<void> clear(ID id) async {
_bot._handlerScopes.removeWhere(
(scope) =>
scope.isConversation &&
(scope.name?.startsWith(name) ?? false) &&
scope.chatId == id,
);
final subsToCancel =
_subscriptionsList.where((sub) => sub.scope.startsWith(name));
await Future.wait(subsToCancel.map((sub) => sub.cancel()));
_subscriptionsList.removeWhere((sub) => sub.scope.startsWith(name));
}