修复定时器获取bot为空导致异常问题

src/main/java/com/yutou/qqbot/utlis/ApplicationInit.java

@@ -33,6 +33,9 @@ public class ApplicationInit implements ApplicationRunner {
                         new Thread(() -> {
                             try {
                                 Bot bot = QQBotManager.getInstance().getBot();
+                                if(bot==null){
+                                    return;
+                                }
                                 Model useModel = (Model) model.getDeclaredConstructor().newInstance();
                                 for (Group group : bot.getGroups()) {
                                     if (QQNumberManager.getManager().isUseModel(group.getId(), model)) {