Fix context menu caching bug

Summary:
The memoized callback didn't have any dependencies, so whenever a context menu was computed for a component, it was never changed again.

This broke the network plugin as the context menu should change depending on what element is selected.

Reviewed By: cekkaewnumchai

Differential Revision: D20596750

fbshipit-source-id: 275453d972079954e310fd3e97f2dd9f437bf748

desktop/app/src/ui/components/ContextMenu.tsx

@@ -47,7 +47,7 @@ export default function ContextMenu<C>({
     } else if (buildItems != null) {
       contextMenuManager?.appendToContextMenu(buildItems());
     }
-  }, []);
+  }, [items, buildItems]);
   return createElement(
     component || FlexColumn,
     {