Chat
Composable function for the top app bar on the chat list screen.
This app bar includes:
A title "Chat List".
A menu icon that invokes openDrawer.
An action button that navigates back to the chatbot screen using onNavigateToChatbot.
Parameters
open
Lambda function to open the navigation drawer when the menu icon is clicked.
on
Lambda function to navigate to the chatbot screen when the button is clicked.