fix(message/detail): 附件不存在时也显示空的unicard

pages/message/detail/index.vue

@@ -33,8 +33,8 @@
 				
 			</view>
 		</uni-card>
-		<uni-card>
-			<view v-if="attachments.length>0">
+		<uni-card  v-if="attachments.length>0">
+			<view>
 				<attachment-list :attachments="attachments" ></attachment-list>
 			</view>
 		</uni-card>