feat: Fetch conversation list by @tanstack/react-query and displays error message that task_executor does not exist #2088 (#2112)

### What problem does this PR solve?

feat: Fetch conversation list by @tanstack/react-query
feat: Displays error message that task_executor does not exist

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/utils/chat.ts

@@ -0,0 +1,5 @@
+import { EmptyConversationId } from '@/constants/chat';
+
+export const isConversationIdExist = (conversationId: string) => {
+  return conversationId !== EmptyConversationId && conversationId !== '';
+};