Properly deserialize active pane in the workspace (#19744)

Without setting the active pane metadata, no center pane events are
emitted on start before the pane is focused manually, which breaks
deserialization of other components like outline panel, which should
show the active pane's active item outlines on start.

Release Notes:

- N/A

Co-authored-by: Thorsten Ball <[email protected]>

crates/workspace/src/workspace.rs

@@ -2947,9 +2947,7 @@ impl Workspace {
             status_bar.set_active_pane(&pane, cx);
         });
         if self.active_pane != pane {
-            self.active_pane = pane.clone();
-            self.active_item_path_changed(cx);
-            self.last_active_center_pane = Some(pane.downgrade());
+            self.set_active_pane(&pane, cx);
         }
 
         if self.last_active_center_pane.is_none() {
@@ -2972,6 +2970,12 @@ impl Workspace {
         cx.notify();
     }
 
+    fn set_active_pane(&mut self, pane: &View<Pane>, cx: &mut ViewContext<Self>) {
+        self.active_pane = pane.clone();
+        self.active_item_path_changed(cx);
+        self.last_active_center_pane = Some(pane.downgrade());
+    }
+
     fn handle_panel_focused(&mut self, cx: &mut ViewContext<Self>) {
         self.update_active_view_for_followers(cx);
     }
@@ -4263,12 +4267,11 @@ impl Workspace {
 
                     // Swap workspace center group
                     workspace.center = PaneGroup::with_root(center_group);
-                    workspace.last_active_center_pane = active_pane.as_ref().map(|p| p.downgrade());
                     if let Some(active_pane) = active_pane {
-                        workspace.active_pane = active_pane;
+                        workspace.set_active_pane(&active_pane, cx);
                         cx.focus_self();
                     } else {
-                        workspace.active_pane = workspace.center.first_pane().clone();
+                        workspace.set_active_pane(&workspace.center.first_pane(), cx);
                     }
                 }