iOS上报错： Unimplemented component: <ModalHostView>

官方并没有开启iOS中modal的Fabric功能，所以只能自己先修改源码

1. 找到头文件RCTFabricComponentsPlugins.h，添加下面代码 Class<RCTComponentViewProtocol> RCTModalHostViewCls(void) __attribute__((used));

2. 找到RCTFabricComponentsPlugins.mm，添加下面代码
   {"ModalHostView", RCTModalHostViewCls}

Class<RCTComponentViewProtocol> RCTFabricComponentsProvider(const char *name) {
  static std::unordered_map<std::string, Class (*)(void)> sFabricComponentsClassMap = {
    {"SafeAreaView", RCTSafeAreaViewCls},
    {"ScrollView", RCTScrollViewCls},
    {"PullToRefreshView", RCTPullToRefreshViewCls},
    {"ActivityIndicatorView", RCTActivityIndicatorViewCls},
    {"Slider", RCTSliderCls},
    {"Switch", RCTSwitchCls},
    {"UnimplementedNativeView", RCTUnimplementedNativeViewCls},
    {"Paragraph", RCTParagraphCls},
    {"TextInput", RCTTextInputCls},
    {"InputAccessoryView", RCTInputAccessoryCls},
    {"View", RCTViewCls},
    {"Image", RCTImageCls},
    {"ModalHostView", RCTModalHostViewCls},
  };

  auto p = sFabricComponentsClassMap.find(name);
  if (p != sFabricComponentsClassMap.end()) {
    auto classFunc = p->second;
    return classFunc();
  }
  return RCTThirdPartyFabricComponentsProvider(name);
}