sidebar-delete-button updated

[Shaan2522]

Fixes #185

This PR updates the frontend\src\components\sidebar\nav-agents.tsx file in order to make the delete button work.

Previously, the delete button was unable to delete a specific chat from the chat history shown in the sidebar. Now, the delete button works perfectly well and deletes a specific chat from the chat history shown in the sidebar once the user clicks on delete button.

eg. delete this button titled chat is deleted.

before clicking delete

after clicking delete