debugger: Fix allow showing more than 1 compact session item (#37036)

Closes #36978

This PR fixes an issue that we would only show the first `root -> child`
session in compact mode, but the session that came after it, we would
only show the child session label instead of also adding the parent
label due to compact mode.

## Before
<img width="348" height="173" alt="Screenshot 2025-08-27 at 22 18 39"
src="https://github.com/user-attachments/assets/ad6afd3a-196d-497f-812a-00698676ee90"
/>

## After
<img width="563" height="211" alt="Screenshot 2025-08-27 at 21 57 16"
src="https://github.com/user-attachments/assets/a953ef2a-a796-4160-b868-96e96f81c858"
/>

With 3 parent + child sessions and one parent session only.
<img width="484" height="223" alt="Screenshot 2025-08-27 at 22 22 13"
src="https://github.com/user-attachments/assets/a26f79a4-63a5-43d0-a714-d62cb1995e6e"
/>

cc @cole-miller I know we hacked on this some while ago, so figured you
might be the best guy to ask for a review.

Release Notes:

- Debugger: Fix to allow showing more than 1 compact session item

---------

Co-authored-by: Anthony <anthony@zed.dev>

crates/debugger_ui/src/dropdown_menus.rs

@@ -113,23 +113,6 @@ impl DebugPanel {
                 }
             };
             session_entries.push(root_entry);
-
-            session_entries.extend(
-                sessions_with_children
-                    .by_ref()
-                    .take_while(|(session, _)| {
-                        session
-                            .read(cx)
-                            .session(cx)
-                            .read(cx)
-                            .parent_id(cx)
-                            .is_some()
-                    })
-                    .map(|(session, _)| SessionListEntry {
-                        leaf: session.clone(),
-                        ancestors: vec![],
-                    }),
-            );
         }
 
         let weak = cx.weak_entity();