RNTester / RCTReactNativeFactory remove unused new architecture flags

Summary:
Changelog: [INTERNAL]

Values are already `true`/YES

```
      [[RCTRootViewFactoryConfiguration alloc] initWithBundleURLBlock:bundleUrlBlock
                                                       newArchEnabled:YES
                                                   turboModuleEnabled:YES
                                                    bridgelessEnabled:YES];
```

Differential Revision: D107305248

Author: christophpurrer

packages/react-native/Libraries/AppDelegate/RCTReactNativeFactory.mm

@@ -132,28 +132,6 @@ - (JSRuntimeFactoryRef)createJSRuntimeFactory
   return [_delegate createJSRuntimeFactory];
 }
 
-#pragma mark - RCTArchConfiguratorProtocol
-
-- (BOOL)newArchEnabled
-{
-  return YES;
-}
-
-- (BOOL)fabricEnabled
-{
-  return YES;
-}
-
-- (BOOL)turboModuleEnabled
-{
-  return YES;
-}
-
-- (BOOL)bridgelessEnabled
-{
-  return YES;
-}
-
 #pragma mark - RCTTurboModuleManagerDelegate
 
 - (Class)getModuleClassFromName:(const char *)name

packages/rn-tester/RNTester/AppDelegate.mm

@@ -159,13 +159,6 @@ - (void)userNotificationCenter:(UNUserNotificationCenter *)center
 }
 #endif
 
-#pragma mark - New Arch Enabled settings
-
-- (BOOL)bridgelessEnabled
-{
-  return YES;
-}
-
 #pragma mark - RCTComponentViewFactoryComponentProvider
 
 #ifndef RN_DISABLE_OSS_PLUGIN_HEADER