Remove translation for changed message

_locales/zh_CN/messages.json

@@ -504,10 +504,6 @@
 		"message": "主题",
 		"description": "Label for the style editor's CSS theme."
 	},
-	"backupMessage": {
-		"message": "导入大文件可能耗时较长，请等待完成通知。",
-		"description": "Message for backup"
-	},
 	"helpKeyMapCommand": {
 		"message": "输入命令名称",
 		"description": "Placeholder text of inputbox in keymap help popup on the edit style page. Must be very short"
@@ -516,4 +512,4 @@
 		"message": "Stylus 是一个调整网页外观的用户样式管理器。它可让您轻松地为许多热门网站网站安装主题和皮肤。",
 		"description": "Extension description"
 	}
-}
+}