Guard tvOS-unavailable APIs in RCTRedBox2Controller (#56568)

Summary:
Pull Request resolved: #56568

`separatorStyle` and `UITableViewCellSeparatorStyleNone` are unavailable on tvOS, causing the airwave-tvos-appletvos build to fail. Wrap them with `#if !TARGET_OS_TV`, matching the existing pattern in `RCTRedBoxController.mm`.

Changelog: [Internal]

Reviewed By: motiz88

Differential Revision: D102001404

fbshipit-source-id: 383e1cc64070000c258b71a60aa4b4ef6453206e

Author: kastopia

packages/react-native/React/CoreModules/RCTRedBox2Controller.mm

@@ -99,7 +99,9 @@ - (void)viewDidLoad
   _stackTraceTableView.delegate = self;
   _stackTraceTableView.dataSource = self;
   _stackTraceTableView.backgroundColor = [UIColor clearColor];
+#if !TARGET_OS_TV
   _stackTraceTableView.separatorStyle = UITableViewCellSeparatorStyleNone;
+#endif
   _stackTraceTableView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
   _stackTraceTableView.bounces = NO;
   [self.view addSubview:_stackTraceTableView];