Add Notification Toaster

[ank1traj]

Currently, the application lacks a notification toaster to provide feedback to the user after performing certain actions such as generating test cases, copying values to clipboard, etc. This can lead to confusion and frustration for users who may not be sure if their actions have been successful or not. Therefore, it would be helpful to add a notification toaster that provides clear feedback to the user after completing these actions.

The notification toaster should be located at the bottom of the screen and should display a message indicating the success or failure of the action along with an appropriate icon. It should also disappear automatically after a few seconds to avoid cluttering the screen. This will enhance the user experience and make the application more user-friendly.