fix: msg page layout

lib/models/msg/like.dart

@@ -39,7 +39,7 @@ class Total {
   List<MessageLikeItem>? items;
 
   factory Total.fromJson(Map<String, dynamic> json) => Total(
-        cursor: Cursor.fromJson(json['cursor']),
+        cursor: json['cursor'] != null ? Cursor.fromJson(json['cursor']) : null,
         items: json["items"] == null
             ? []
             : json["items"].map<MessageLikeItem>((e) {

lib/models/msg/session.dart

@@ -13,8 +13,9 @@ class SessionDataModel {
 
   SessionDataModel.fromJson(Map<String, dynamic> json) {
     sessionList = json['session_list']
-        ?.map<SessionList>((e) => SessionList.fromJson(e))
-        .toList();
+            ?.map<SessionList>((e) => SessionList.fromJson(e))
+            .toList() ??
+        [];
     hasMore = json['has_more'];
   }
 }