fix download assets functionality, fix strings.xml

V2rayNG/app/src/main/res/values-zh-rTW/strings.xml

@@ -82,6 +82,8 @@
     <string name="menu_item_download_file">下載檔案</string>
 
     <!-- PerAppProxyActivity -->
+    <string name="title_user_asset_add_url">新增資產網址</string>
+    <string name="msg_file_not_found">文件未找到</string>
     <string name="msg_dialog_progress">載入</string>
     <string name="menu_item_search">搜尋</string>
     <string name="menu_item_select_all">全選</string>