fix flutter#6

Author: PeterOmbodi

packages/video_player/video_player/ios/Classes/FLTVideoPlayerPlugin.m

@@ -330,7 +330,7 @@ - (void)sendInitialized {
       //return;
     }
 
-    _isInitialized = true;
+    //_isInitialized = true;
     _eventSink(@{
       @"event" : @"initialized",
       @"duration" : @([self duration]),