Repository: flutter
Issue: [Webview_flutter]: The screen that has a flutter web page doesn't scroll properly after closing dialog box. 
Labels: platform-ios,p: webview,package,has reproducible steps,P2,found in release: 2.10,found in release: 2.13,team-ios,triaged-ios

## Steps to Reproduce

I have such a problem when using webview_flutter, opening the flutter web page for the first time can slide normally, the click event in the page is also normal, you can perform the click behavior.The problem is, when I try to slide off (cancel back halfway), the page scroll is not so smooth and the page doesn't perform click behavior.There is also a way to test that the page is not smooth. After opening the flutter web page, if you open a dialog box, when the dialog box closes, the flutter web page is not smooth, and can not respond to gestures normally.

1. Execute `flutter run` on the code sample <!-- (see "Code sample" section below) -->
2. Open a new page, add a button to the appBar, and use the WebView in the body;
3. Enter the page for the first time, everything is normal, if then click the ammonium button on the appBar to open a dialog box, after the dialog box is closed, the page scroll abnormal.

**Expected results:** The flutter web page responds normally to gesture slide and click events

**Actual results:** The page does not scroll smoothly and cannot respond to events properly

<details>
<summary>Code sample</summary>

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```dart
class BrowserPage extends StatefulWidget {
  const BrowserPage({Key? key}) : super(key: key);

  @override
  State<BrowserPage> createState() => _BrowserPageState();
}

class _BrowserPageState extends State<BrowserPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Web Browser'),
        actions: [
          IconButton(
            onPressed: () {
              showDialog<void>(
                context: context,
                barrierDismissible: true,
                builder: (BuildContext dialogContext) {
                  return AlertDialog(
                    title: const Text('Dialog'),
                    content: const Text('Test dialog body.'),
                    actions: <Widget>[
                      TextButton(
                        child: const Text('Close'),
                        onPressed: () {
                          Navigator.of(dialogContext).pop();
                        },
                      ),
                    ],
                  );
                },
              );
            },
            icon: const Icon(Icons.add),
          ),
        ],
      ),
      body: WebView(
        initialUrl: 'http://192.168.1.68:8000/brand_list',
        debuggingEnabled: true,
        gestureNavigationEnabled: true,
        javascriptMode: JavascriptMode.unrestricted,
        onWebViewCreated: (controller) {
          controller.currentUrl().then((value) => debugPrint(value));
        },
        onProgress: (int progress) {
          debugPrint("WebView is loading (progress : $progress%)");
        },
      ),
    );
  }
}
```

</details>

<details>
  <summary>Logs</summary>

<!--
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      log output below between the lines with the backticks. If there is an
      exception, please see if the error message includes enough information
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<!--
     Run `flutter analyze` and attach any output of that command below.
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```
Analyzing flutter_mall_demo...                                          
No issues found! (ran in 1.6s)
```

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 2.10.4, on macOS 12.3 21E230 darwin-arm, locale zh-Hans-CN)
[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 13.3)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2021.1)
[✓] IntelliJ IDEA Ultimate Edition (version 2021.2.3)
[✓] VS Code (version 1.66.0)
[✓] Connected device (3 available)
[✓] HTTP Host Availability

• No issues found!
```

</details>


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https://user-images.githubusercontent.com/5601597/162562092-27863db4-38e0-48c8-afdc-e004fc2ed3f8.mp4