Adds unread message bubbles for widget (#943)

Co-authored-by: Sojan <sojan@pepalo.com>
Co-authored-by: Pranav Raj S <pranav@thoughtwoot.com>

app/javascript/widget/api/conversation.js

@@ -30,10 +30,18 @@ const toggleTyping = async ({ typingStatus }) => {
   );
 };
 
+const setUserLastSeenAt = async ({ lastSeen }) => {
+  return API.post(
+    `/api/v1/widget/conversations/update_last_seen${window.location.search}`,
+    { user_last_seen_at: lastSeen }
+  );
+};
+
 export {
   sendMessageAPI,
   getConversationAPI,
   getMessagesAPI,
   sendAttachmentAPI,
   toggleTyping,
+  setUserLastSeenAt,
 };