修复无法添加动态的问题

lib/ui/community/community_views/add_new_event_page.dart

@@ -203,6 +203,7 @@ class _AddNewEventPageState extends State<AddNewEventPage> {
           Divider(height: 1.w),
           28.hb,
           if (widget.initTopic == null) _pickTopic(),
+          if (widget.initTopic != null)
             Align(
               alignment: Alignment.centerLeft,
               child: _renderTopic(