Last chat history bubble is not selected when scrolled to the bottom

@osortega, sometimes the last chat history bubbles can not be rendered as active/selected.

**Expected**

I think the last chat history bubble should be selected when the user scrolls all the way to the bottom, even if the top of the chat viewport still shows content from the previous chat request.

**Actual**

At the bottom of the chat, it is possible for the second to last bubble to appears active/selected.

**Recording**

https://github.com/user-attachments/assets/83ce09aa-4345-4913-8a2a-d21d81a332e0