fix(player): 调整 rail 倍速弹窗与进度时间

test/playback/seek_progress_bar_test.dart

@@ -56,11 +56,13 @@ void main() {
     await tester.pump();
     expect(started, 1);
     expect(target, isNull);
+    expect(find.textContaining('/ 00:12'), findsOneWidget);
     await gesture.up();
     await tester.pumpAndSettle();
     expect(target, isNotNull);
     expect(target!, greaterThan(const Duration(seconds: 3)));
     expect(target!, lessThan(const Duration(seconds: 12)));
+    expect(find.textContaining('/ 00:12'), findsNothing);
   });
 
   testWidgets('should_show_time_only_while_dragging_when_seek_bar_is_compact', (