Fix error on refresh while a folder watch is being set up

Notes:

From QA

> This error mostly happens if i add a watch folder and before watch folders
  start to upload and i refresh the app.

e is undefined in

    let {watches: e, removeWatch: n} = t;
    return 0 === e.length ? (0,...

Results in Next throwing

    Application error: a client-side exception has occurred (see the browser console for more information).

web/apps/photos/src/components/WatchFolder.tsx

@@ -153,12 +153,12 @@ const Title_ = styled("div")`
 `;
 
 interface WatchList {
-    watches: FolderWatch[];
+    watches: FolderWatch[] | undefined;
     removeWatch: (watch: FolderWatch) => void;
 }
 
 const WatchList: React.FC<WatchList> = ({ watches, removeWatch }) => {
-    return watches.length === 0 ? (
+    return (watches ?? []).length === 0 ? (
         <NoWatches />
     ) : (
         <WatchesContainer>