Use better fallback for empty rerun action (#32031)

When invoking the task rerun action before any task had been run, it
falls back to task selection modal.
Adjust this fall back to use the debugger view, if available:

Before:

![before](https://github.com/user-attachments/assets/737d2dc1-15a4-4eea-a5f9-4aff6c7600cc)


After:

![after](https://github.com/user-attachments/assets/43381b85-5167-44e7-a8b0-865a64eaa6ea)


Release Notes:

- N/A

crates/tasks_ui/src/tasks_ui.rs

@@ -80,7 +80,14 @@ pub fn init(cx: &mut App) {
                             );
                         }
                     } else {
-                        toggle_modal(workspace, None, window, cx).detach();
+                        spawn_task_or_modal(
+                            workspace,
+                            &Spawn::ViaModal {
+                                reveal_target: None,
+                            },
+                            window,
+                            cx,
+                        );
                     };
                 });
         },