Add loader for memories widget

lib/ui/home/memories/memories_widget.dart

@@ -6,6 +6,7 @@ import "package:photos/core/event_bus.dart";
 import "package:photos/events/memories_setting_changed.dart";
 import 'package:photos/models/memory.dart';
 import 'package:photos/services/memories_service.dart';
+import "package:photos/ui/common/loading_widget.dart";
 import 'package:photos/ui/home/memories/memory_cover_widget.dart';
 
 class MemoriesWidget extends StatefulWidget {
@@ -63,6 +64,7 @@ class _MemoriesWidgetState extends State<MemoriesWidget> {
         if (snapshot.hasError || !snapshot.hasData) {
           return SizedBox(
             height: _maxHeight + 12 + 10,
+            child: const EnteLoadingWidget(),
           );
         } else {
           return Column(