Add `history.deleteChat()`

[adamlui]

Discussed in #176

^{Originally posted by gadelkareem January 13, 2024:}

I couldn't find a delete chat func, would be great if added.

Here is playwright code to delete current chat:

        page.get_by_label("Chat history").get_by_role("button").nth(1).click()
        page.get_by_text("Delete chat").click()
        page.get_by_role("button", name="Delete").click()
```</div>