consolidated downloads dir, nextcloud origin, upload route and chat timestamps; added webdav path tests

lib/view/pages/talk/details/shared_items_view.dart

@@ -511,7 +511,7 @@ class _SharedItemTileState extends State<_SharedItemTile>
   }
 
   String get _previewUrl =>
-      'https://${EndpointData().nextcloud().full()}'
+      '${EndpointData().nextcloud().origin()}'
       '/index.php/core/preview?fileId=${_file.id}&x=300&y=300&a=1';
 
   bool get _isVideo => _isVideoFile(_file.name);
@@ -586,7 +586,7 @@ class _SharedItemTileState extends State<_SharedItemTile>
     title: Text(_file.name, maxLines: 2, overflow: TextOverflow.ellipsis),
     subtitle: Text(
       '${widget.item.actorDisplayName} · '
-      '${DateTime.fromMillisecondsSinceEpoch(widget.item.timestamp * 1000).formatDateShort()}',
+      '${widget.item.sentAt.formatDateShort()}',
     ),
     trailing: _isDownloading
         ? SizedBox(