Extract auto_update_ui crate (#21008)

This PR extracts an `auto_update_ui` crate out of the `auto_update`
crate.

This allows `auto_update` to not depend on heavier crates like `editor`,
which in turn allows other downstream crates to start building sooner.

Release Notes:

- N/A

crates/auto_update_ui/src/update_notification.rs

@@ -0,0 +1,68 @@
+use gpui::{
+    div, DismissEvent, EventEmitter, InteractiveElement, IntoElement, ParentElement, Render,
+    SemanticVersion, StatefulInteractiveElement, Styled, ViewContext, WeakView,
+};
+use menu::Cancel;
+use release_channel::ReleaseChannel;
+use util::ResultExt;
+use workspace::{
+    ui::{h_flex, v_flex, Icon, IconName, Label, StyledExt},
+    Workspace,
+};
+
+pub struct UpdateNotification {
+    version: SemanticVersion,
+    workspace: WeakView<Workspace>,
+}
+
+impl EventEmitter<DismissEvent> for UpdateNotification {}
+
+impl Render for UpdateNotification {
+    fn render(&mut self, cx: &mut gpui::ViewContext<Self>) -> impl IntoElement {
+        let app_name = ReleaseChannel::global(cx).display_name();
+
+        v_flex()
+            .on_action(cx.listener(UpdateNotification::dismiss))
+            .elevation_3(cx)
+            .p_4()
+            .child(
+                h_flex()
+                    .justify_between()
+                    .child(Label::new(format!(
+                        "Updated to {app_name} {}",
+                        self.version
+                    )))
+                    .child(
+                        div()
+                            .id("cancel")
+                            .child(Icon::new(IconName::Close))
+                            .cursor_pointer()
+                            .on_click(cx.listener(|this, _, cx| this.dismiss(&menu::Cancel, cx))),
+                    ),
+            )
+            .child(
+                div()
+                    .id("notes")
+                    .child(Label::new("View the release notes"))
+                    .cursor_pointer()
+                    .on_click(cx.listener(|this, _, cx| {
+                        this.workspace
+                            .update(cx, |workspace, cx| {
+                                crate::view_release_notes_locally(workspace, cx);
+                            })
+                            .log_err();
+                        this.dismiss(&menu::Cancel, cx)
+                    })),
+            )
+    }
+}
+
+impl UpdateNotification {
+    pub fn new(version: SemanticVersion, workspace: WeakView<Workspace>) -> Self {
+        Self { version, workspace }
+    }
+
+    pub fn dismiss(&mut self, _: &Cancel, cx: &mut ViewContext<Self>) {
+        cx.emit(DismissEvent);
+    }
+}