Crash the app when Legacy Arch is enabled

packages/react-native/React/Base/RCTBridge.mm

@@ -380,6 +380,11 @@ - (instancetype)initWithDelegate:(id<RCTBridgeDelegate>)delegate
                   moduleProvider:(RCTBridgeModuleListProvider)block
                    launchOptions:(NSDictionary *)launchOptions
 {
+  // Only enabld this assertion in OSS
+#if COCOAPODS
+  [RCTBridge throwIfOnLegacyArch];
+#endif
+
   if (self = [super init]) {
     RCTEnforceNewArchitectureValidation(RCTNotAllowedInBridgeless, self, nil);
     _delegate = delegate;
@@ -393,6 +398,17 @@ - (instancetype)initWithDelegate:(id<RCTBridgeDelegate>)delegate
   return self;
 }
 
+// Wrap the exception throwing in a static method to avoid the warning: "The code following the exception will never be
+// executed". This might create build failures internally where we treat warnings as errors.
++ (void)throwIfOnLegacyArch
+{
+  @throw [NSException
+      exceptionWithName:NSInternalInconsistencyException
+                 reason:
+                     @"You are trying to initialize the legacy architecture. This is not supported anymore and will be removed in the next version of React Native. Please use the New Architecture instead."
+               userInfo:nil];
+}
+
 RCT_NOT_IMPLEMENTED(-(instancetype)init)
 
 - (void)dealloc