Dont allow focusing leaf node

Summary: This mode is useless for leaves

Reviewed By: aigoncharov

Differential Revision: D47949539

fbshipit-source-id: 7f3ae6652ad696e9f550fe5b8f2298a1a3eff329

desktop/plugins/public/ui-debugger/utils/map.tsx

@@ -0,0 +1,15 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import {ClientNode, Id} from '../ClientTypes';
+
+export function getNode(id: Id | undefined, nodes: Map<Id, ClientNode>) {
+  //map just returns undefined when you pass null or undefined as a key
+  return nodes.get(id!);
+}