opt: unnecessary_non_null_assertion (#1762)

lib/pages/dynamics/widgets/content_panel.dart

@@ -88,10 +88,10 @@ Widget content(
                   onShowMore: () => PageUtils.pushDynDetail(item, isPush: true),
                   primary: theme.colorScheme.primary,
                 ),
-        if (pics?.isNotEmpty == true)
+        if (pics != null && pics.isNotEmpty)
           CustomGridView(
             maxWidth: maxWidth,
-            picArr: pics!
+            picArr: pics
                 .map(
                   (item) => ImageModel(
                     width: item.width,

lib/pages/dynamics/widgets/rich_node_panel.dart

@@ -294,8 +294,8 @@ TextSpan? richNode(
                           } else {
                             i.dynPic = list;
                           }
-                          if (list?.isNotEmpty == true) {
-                            onView(list!);
+                          if (list != null && list.isNotEmpty) {
+                            onView(list);
                           }
                         } else {
                           res.toast();

lib/pages/dynamics/widgets/up_panel.dart

@@ -94,9 +94,9 @@ class _UpPanelState extends State<UpPanel> {
             ),
           ),
         ),
-        if (controller.showLiveUp && liveList?.isNotEmpty == true)
+        if (controller.showLiveUp && liveList != null && liveList.isNotEmpty)
           SliverList.builder(
-            itemCount: liveList!.length,
+            itemCount: liveList.length,
             itemBuilder: (context, index) {
               return upItemBuild(theme, liveList[index]);
             },