Remove left-over ToDo comment

src/components/App.tsx

@@ -3563,7 +3563,6 @@ class App extends React.Component<ExcalidrawProps, AppState> {
           // This will only work as of Chrome 86,
           // but can be safely ignored on older releases.
           const item = event.dataTransfer.items[0];
-          // TODO: Make this part of `AppState`.
           (file as any).handle = await (item as any).getAsFileSystemHandle();
         } catch (error) {
           console.warn(error.name, error.message);