Revert "Enable New UI by default (#1460)" (#1476)

This reverts commit f0b735f3dd.

src/i18n.ts

@@ -2,8 +2,6 @@ import { createI18n } from 'vue-i18n'
 
 const messages = {
   en: {
-    firstTimeUIMessage:
-      'This is the first time you use the new UI. Choose "Menu > Use New Menu > Disabled" to restore the old UI.',
     download: 'Download',
     loadAllFolders: 'Load All Folders',
     refresh: 'Refresh',
@@ -127,8 +125,6 @@ const messages = {
     }
   },
   zh: {
-    firstTimeUIMessage:
-      '这是您第一次使用新界面。选择“Menu > Use New Menu > Disabled”以恢复旧界面。',
     download: '下载',
     loadAllFolders: '加载所有文件夹',
     refresh: '刷新',