NativeModules iOS: downgrade duplicated module message to warning instead of error

Summary: [iOS] [Changed] - There seems to be a potential race condition during reloading that could cause "double registration" of modules. This should be mostly harmless, so downgrade to warning for the message instead of redboxing.

Reviewed By: cpojer

Differential Revision: D14179922

fbshipit-source-id: 5c16ac674f633a548353277d9f875544ed10ba9b

React/CxxBridge/RCTCxxBridge.mm

@@ -615,9 +615,9 @@ struct RCTInstanceCallback : public InstanceCallback {
         continue;
       } else if ([moduleData.moduleClass new] != nil) {
         // Both modules were non-nil, so it's unclear which should take precedence
-        RCTLogError(@"Attempted to register RCTBridgeModule class %@ for the "
-                    "name '%@', but name was already registered by class %@",
-                    moduleClass, moduleName, moduleData.moduleClass);
+        RCTLogWarn(@"Attempted to register RCTBridgeModule class %@ for the "
+                   "name '%@', but name was already registered by class %@",
+                   moduleClass, moduleName, moduleData.moduleClass);
       }
     }