fix(mobile): better UI for metadata panel (#24428)

* change drag bar and animation position

* ensure bottom bar is below the metadata panel - move the bottom bar from bottomNavigationBar into the Stack

* change some parameters

* add background color for night mode

* background color

* change default position

* minor changes

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Co-authored-by: Alex <alex.tran1502@gmail.com>

mobile/lib/presentation/widgets/asset_viewer/activities_bottom_sheet.widget.dart

@@ -79,7 +79,7 @@ class ActivitiesBottomSheet extends HookConsumerWidget {
       expand: false,
       shouldCloseOnMinExtent: false,
       resizeOnScroll: false,
-      backgroundColor: context.isDarkTheme ? Colors.black : Colors.white,
+      backgroundColor: context.isDarkTheme ? context.colorScheme.surface : Colors.white,
     );
   }
 }