Start on adding support for editing via the assistant panel (#14795)

Note that this shouldn't have any visible user-facing behavior yet. The
feature is incomplete but we wanna merge early to avoid a long-running
branch.

Release Notes:

- N/A

---------

Co-authored-by: Nathan <nathan@zed.dev>

crates/extensions_ui/src/extensions_ui.rs

@@ -48,10 +48,10 @@ pub fn init(cx: &mut AppContext) {
                     .find_map(|item| item.downcast::<ExtensionsPage>());
 
                 if let Some(existing) = existing {
-                    workspace.activate_item(&existing, cx);
+                    workspace.activate_item(&existing, true, true, cx);
                 } else {
                     let extensions_page = ExtensionsPage::new(workspace, cx);
-                    workspace.add_item_to_active_pane(Box::new(extensions_page), None, cx)
+                    workspace.add_item_to_active_pane(Box::new(extensions_page), None, true, cx)
                 }
             })
             .register_action(move |workspace, _: &InstallDevExtension, cx| {