Display what the tool is doing (#27120)

<img width="639" alt="Screenshot 2025-03-19 at 4 56 47 PM"
src="https://github.com/user-attachments/assets/b997f04d-4aff-4070-87b1-ffdb61019bd1"
/>

Release Notes:

- N/A

---------

Co-authored-by: Agus Zubiaga <hi@aguz.me>

crates/assistant_eval/src/headless_assistant.rs

@@ -128,12 +128,7 @@ impl HeadlessAssistant {
                     }
                 }
             }
-            ThreadEvent::StreamedCompletion
-            | ThreadEvent::SummaryChanged
-            | ThreadEvent::StreamedAssistantText(_, _)
-            | ThreadEvent::MessageAdded(_)
-            | ThreadEvent::MessageEdited(_)
-            | ThreadEvent::MessageDeleted(_) => {}
+            _ => {}
         }
     }
 }