fix：专栏图文渲染异常

lib/pages/member_article/controller.dart

@@ -20,7 +20,7 @@ class MemberArticleController extends GetxController {
   }
 
   Future getMemberArticle(type) async {
-    if (isLoading.value) {
+    if (isLoading.value || !hasMore) {
       return;
     }
     isLoading.value = true;

lib/pages/member_article/view.dart

@@ -113,12 +113,14 @@ class _MemberArticlePageState extends State<MemberArticlePage> {
           'articleType': 'opus',
         });
       },
-      leading: NetworkImgLayer(
+      leading: item?.cover != null
+          ? NetworkImgLayer(
               width: 50,
               height: 50,
               type: 'emote',
               src: item?.cover?['url'] ?? '',
-      ),
+            )
+          : const SizedBox(),
       title: Text(
         item.content,
         maxLines: 2,