chore: Remove outline dependency from breadcrumbs (#22504)

This slashes our incremental dev times (touch editor) by 0.6s
(8.1->7.6s) due to unblocking terminal_view build sooner.

Closes #ISSUE

Release Notes:

- N/A

crates/editor/src/actions.rs

@@ -388,6 +388,4 @@ gpui::actions!(
     ]
 );
 
-action_as!(outline, ToggleOutline as Toggle);
-
 action_as!(go_to_line, ToggleGoToLine as Toggle);