Web: Detect if the user has not interacted with the page yet

On web, autoplay does not work if the user has not interacted with the page yet.

This example shows a broken video without the ability to play it:

```dart
import 'package:chewie/chewie.dart';
import 'package:flutter/material.dart';
import 'package:video_player/video_player.dart';

late VideoPlayerController videoPlayerController;
late ChewieController chewieController;
final routerDelegate = MyRouterDelegate();

Future main() async {
WidgetsFlutterBinding.ensureInitialized();

videoPlayerController =
VideoPlayerController.networkUrl(Uri.parse('https://flutter.github.io/assets-for-api-docs/assets/videos/bee.mp4'));

await videoPlayerController.initialize();
chewieController = ChewieController(
videoPlayerController: videoPlayerController,
autoPlay: true,
);

runApp(MyApp());
}

class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp.router(
routerDelegate: routerDelegate,
);
}
}

class MyRouterDelegate extends RouterDelegate
with ChangeNotifier, PopNavigatorRouterDelegateMixin {
@override
final GlobalKey navigatorKey = GlobalKey();

@override
Widget build(BuildContext context) {
return Navigator(
pages: [
MaterialPage(
key: ValueKey('HomePage'),
child: Chewie(controller: chewieController),
),
],
onPopPage: (route, result) => true,
);
}

@override
Future setNewRoutePath(configuration) async {}
}
```

For some reason, I don't see an error in the console, but if I add `print(e);` to the error handler in `video_player.dart`, it shows this in Chrome:

```
NotAllowedError: play() failed because the user didn't interact with the document first. https://goo.gl/xX8pDD
```

I expect that if autoplay can't work I still have a functional player even if not started automatically.

This happens in the real world with deep linking when people share links to my video pages.