Restyle notification close control (#30262)

Follow-up of https://github.com/zed-industries/zed/pull/30015

Merges suppress and close buttons into one, with `shift` changing the
state and showing different tooltips.
Currently, there's no tooltip for notification suppress action, hence
none is displayed in the video:


https://github.com/user-attachments/assets/678c4d76-a86e-4fe9-8d7b-92996470a8a8

Release Notes:

- N/A

crates/workspace/src/workspace.rs

@@ -5729,6 +5729,11 @@ impl Render for Workspace {
 
         let theme = cx.theme().clone();
         let colors = theme.colors();
+        let notification_entities = self
+            .notifications
+            .iter()
+            .map(|(_, notification)| notification.entity_id())
+            .collect::<Vec<_>>();
 
         client_side_decorations(
             self.actions(div(), window, cx)
@@ -5744,6 +5749,11 @@ impl Render for Workspace {
                 .text_color(colors.text)
                 .overflow_hidden()
                 .children(self.titlebar_item.clone())
+                .on_modifiers_changed(move |_, _, cx| {
+                    for &id in &notification_entities {
+                        cx.notify(id);
+                    }
+                })
                 .child(
                     div()
                         .size_full()