auto_update_ui: Show update notification across workspaces (#23458)

When Zed reopens after an auto-update is installed, a notification was
previously displayed in the first window opened. If there were multiple
windows open, the notification could be hidden because Zed reopens the
last session's window stack in order from back to front. Now, the
notification is opened in every workspace, and dismissing the
notification in any workspace will dismisses it everywhere.

Closes #23236

Release Notes:

- Improved notification after Zed is updated to be visible in all
workspaces.

---------

Co-authored-by: Michael Sloan <michael@zed.dev>

crates/zed/src/zed.rs

@@ -213,8 +213,6 @@ pub fn initialize_workspace(
             status_bar.add_right_item(cursor_position, window, cx);
         });
 
-        auto_update_ui::notify_of_any_new_update(window, cx);
-
         let handle = cx.entity().downgrade();
         window.on_window_should_close(cx, move |window, cx| {
             handle