MessageBox has "false" class

From @mcoker: I noticed `false` being rendered as a class on the `.pf-chatbot__messagebox` element

<img width="642" height="822" alt="Screenshot 2025-07-15 at 11 23 10 AM" src="https://github.com/user-attachments/assets/02eb2054-47d9-4270-b15f-3d3fc0c91fb0" />
