collab_ui: Remove dependency on vcs_menu (#21016)

This PR removes the `vcs_menu` dependency from `collab_ui`.

We were only depending on this to call `vcs_menu::init`, which isn't
necessary to do here.

Release Notes:

- N/A

crates/collab_ui/src/collab_ui.rs

@@ -33,7 +33,6 @@ pub fn init(app_state: &Arc<AppState>, cx: &mut AppContext) {
     notification_panel::init(cx);
     notifications::init(app_state, cx);
     title_bar::init(cx);
-    vcs_menu::init(cx);
 }
 
 fn notification_window_options(