Enable dev keyboard shortcuts on Mac Catalyst (#27479)

Summary:
This enables the dev menu to bo opened from keyboard shortcuts in dev from a Mac Catalyst app.

cc TheSavior andymatuschak radex

## Changelog

[iOS] [Fixed] - Enable dev keyboard shortcuts on Mac Catalyst
Pull Request resolved: https://github.com/facebook/react-native/pull/27479

Test Plan:
It depends on https://github.com/facebook/react-native/issues/27469 (to have working WebSocket in debug).

![image](https://user-images.githubusercontent.com/7189823/70629346-d3a68880-1bf7-11ea-8949-7553157a2f9c.png)

Differential Revision: D19576528

Pulled By: shergin

fbshipit-source-id: 32b4f8424fb7d270640af4bc50dba24f488bef4f

React/CoreModules/RCTDevMenu.mm

@@ -122,7 +122,7 @@ RCT_EXPORT_MODULE()
                                                object:nil];
     _extraMenuItems = [NSMutableArray new];
 
-#if TARGET_OS_SIMULATOR
+#if TARGET_OS_SIMULATOR || TARGET_OS_MACCATALYST
     RCTKeyCommands *commands = [RCTKeyCommands sharedInstance];
     __weak __typeof(self) weakSelf = self;
 

React/CoreModules/RCTRedBox.mm

@@ -116,7 +116,7 @@
         _stackTraceTableView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
         [rootView addSubview:_stackTraceTableView];
 
-#if TARGET_OS_SIMULATOR
+#if TARGET_OS_SIMULATOR || TARGET_OS_MACCATALYST
         NSString *reloadText = @"Reload\n(\u2318R)";
         NSString *dismissText = @"Dismiss\n(ESC)";
         NSString *copyText = @"Copy\n(\u2325\u2318C)";

React/Modules/RCTRedBoxExtraDataViewController.m

@@ -106,7 +106,7 @@
         _tableView.rowHeight = UITableViewAutomaticDimension;
         _tableView.allowsSelection = NO;
 
-#if TARGET_OS_SIMULATOR
+#if TARGET_OS_SIMULATOR || TARGET_OS_MACCATALYST
         NSString *reloadText = @"Reload JS (\u2318R)";
         NSString *dismissText = @"Dismiss (ESC)";
 #else