minor change

Author: iceljc

src/routes/chat/[agentId]/[conversationId]/chat-box.svelte

@@ -1180,7 +1180,7 @@
 		isOpenEditMsgModal = false;
 		const postback = buildPostback(truncateMsgId);
 		deleteConversationMessage(params.conversationId, truncateMsgId, true).then(res => {
-			sendChatMessage(editText, { postback: postback, inputMessageId: res.messageId }).then(() => {
+			sendChatMessage(editText, { postback: postback, inputMessageId: res?.messageId }).then(() => {
 				resetEditMsg();
 			}).catch(() => {
 				resetEditMsg();