refactor(项目管理): 修复自定义js代码请求api时生成的脚本没有判断响应码是否是200的问题

--bug=1014236 --user=宋天阳 【项目管理】自定义代码片段，js语言，导入接口定义，执行报错了
https://www.tapd.cn/55049933/s/1186949

frontend/src/business/components/project/menu/function/custom-function.js

@@ -398,13 +398,16 @@ conn.setRequestMethod(requestMethod);
 conn.setDoOutput(true);
 ${connStr}conn.connect();
 ${postParamExecCode}
+var res = "";
+var rspCode = conn.getResponseCode();
+if (rspCode == 200) {
 var ipt = conn.getInputStream();
 var reader = new java.io.BufferedReader(new java.io.InputStreamReader(ipt, "UTF-8"));
 var lines;
-var res = "";
 while((lines = reader.readLine()) !== null) {
   res += lines;
 }
+}
 log.info(res);
   `;
 }