Use older openURL signature (#3660)

shell/platform/darwin/ios/framework/Headers/FlutterPlugin.h

@@ -34,8 +34,7 @@ NS_ASSUME_NONNULL_BEGIN
     didReceiveRemoteNotification:(NSDictionary*)userInfo
           fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler;
 - (BOOL)application:(UIApplication*)application
-            openURL:(NSURL*)url
-            options:(NSDictionary<UIApplicationOpenURLOptionsKey, id>*)options;
+      handleOpenURL:(NSURL*)url;
 @end
 
 @protocol FlutterPluginRegistrar<NSObject>

shell/platform/darwin/ios/framework/Source/FlutterAppDelegate.mm

@@ -156,11 +156,10 @@
 }
 
 - (BOOL)application:(UIApplication*)application
-            openURL:(NSURL*)url
-            options:(NSDictionary<UIApplicationOpenURLOptionsKey, id>*)options {
+      handleOpenURL:(NSURL*)url {
   for (id<FlutterPlugin> plugin in _pluginDelegates) {
     if ([plugin respondsToSelector:_cmd]) {
-      if ([plugin application:application openURL:url options:options]) {
+      if ([plugin application:application handleOpenURL:url]) {
         return YES;
       }
     }