[feat]修复，无网络时，点击键盘的按键，发送请求报错，要提示网络异常

lib/plugins/keyboard_method_handler.dart

@@ -1,5 +1,6 @@
 import 'dart:convert';
 
+import 'package:dio/dio.dart';
 import 'package:flutter/services.dart';
 
 import 'package:get/get.dart';
@@ -246,10 +247,9 @@ class KeyboardMethodHandler {
       );
     } else {
       AtmobLog.e(tag, "未知异常: $error");
-
       throw PlatformException(
         code: "-1",
-        message: error.toString(),
+        message: "网络异常",
         details: {'code': -1, 'message': error.toString()},
       );
     }