deleteRule method
Delete rule.
Implementation
void deleteRule(String id) {
final value = selected;
if (value == null || value.isSystem) return;
final next = value.responseRules.where((item) => item.id != id).toList();
_update(value.copyWith(responseRules: [for (var i = 0; i < next.length; i++) next[i].copyWith(priority: i)]));
}