fix chats messages

src/components/chat_message/chat_message.js

@@ -58,8 +58,8 @@ const ChatMessage = {
       return {
         summary: '',
         emojis: this.message.emojis,
-        raw_html: this.message.content,
-        text: this.message.content,
+        raw_html: this.message.content || '',
+        text: this.message.content || '',
         attachments: this.message.attachments
       }
     },