Change ElementID to Element for Sidebar Extension

Summary: Element also contains `id`, which is equivalent to ElementID used in the existing extension. This change will help the implementation of layout intern search easier.

Reviewed By: mweststrate

Differential Revision: D21385001

fbshipit-source-id: b8c6e6f052af8cfa54bf3a132571e40567cdee4b

desktop/plugins/layout/InspectorSidebar.tsx

@@ -149,7 +149,7 @@ const Sidebar: React.FC<Props> = (props: Props) => {
   const sections: Array<React.ReactNode> = (
     (SidebarExtensions &&
       SidebarExtensions.map((ext) =>
-        ext(props.client, props.realClient, element.id, props.logger),
+        ext(props.client, props.realClient, element, props.logger),
       )) ||
     []
   ).concat(