Repository: flutter
Issue: [web] Overlay's cursor is overridden by an underlying focused TextField
Labels: framework,platform-web,a: mouse,has reproducible steps,P2,found in release: 2.8,found in release: 2.9,team-web,triaged-web

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## Steps to Reproduce

<!-- Please include full steps to reproduce so that we can reproduce the problem. -->

1. Execute ` flutter run -d chrome` on the code sample <!-- (see "Code sample" section below) -->
2. Hover over empty space, notice that an Overlay's help cursor is displayed
3. Hover over the focused text field, notice that a TextField's text cursor is displayed

**Expected results:** 
A help cursor is displayed for the whole overlay regardless of underlying widgets

**Actual results:**

https://user-images.githubusercontent.com/13119003/148348488-d9548df7-c124-4b91-9398-74810d2a2357.mp4

<details>
<summary>Code sample</summary>

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      and attach it below between the lines with the backticks.

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```dart
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: MyWidget(),
      ),
    );
  }
}

class MyWidget extends StatefulWidget {
  @override
  State<MyWidget> createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  final _focusNode = FocusNode();
  final _controller = TextEditingController(text: "Some text");

  @override
  void initState() {
    super.initState();

    final entry = OverlayEntry(
      builder: (BuildContext context) {
        return Positioned.fill(
          child: MouseRegion(
            cursor: SystemMouseCursors.help,
            child: ColoredBox(
              color: Colors.green.withOpacity(0.1),
            ),
          ),
        );
      },
    );

    WidgetsBinding.instance!.addPostFrameCallback((_) {
      _focusNode.requestFocus();
      Overlay.of(context)!.insert(entry);
    });
  }

  @override
  void dispose() {
    this._controller.dispose();
    this._focusNode.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: SizedBox(
        width: 80,
        child: TextField(
          controller: this._controller,
          focusNode: this._focusNode,
        ),
      ),
    );
  }
}
```

</details>

<details>
  <summary>flutter doctor -v</summary>

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
[✓] Flutter (Channel stable, 2.8.0, on macOS 12.0.1 21A559 darwin-x64, locale en-GB)
    • Flutter version 2.8.0 at /Users/krasnov/sdk/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision cf44000065 (4 weeks ago), 2021-12-08 14:06:50 -0800
    • Engine revision 40a99c5951
    • Dart version 2.15.0

[!] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
    • Android SDK at /Users/krasnov/Library/Android/sdk
    ✗ cmdline-tools component is missing
      Run `path/to/sdkmanager --install "cmdline-tools;latest"`
      See https://developer.android.com/studio/command-line for more details.
    ✗ Android license status unknown.
      Run `flutter doctor --android-licenses` to accept the SDK licenses.
      See https://flutter.dev/docs/get-started/install/macos#android-setup for more details.

[✓] Xcode - develop for iOS and macOS (Xcode 13.2.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • CocoaPods version 1.11.2

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2020.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7281165)

[✓] VS Code (version 1.56.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.22.0

[✓] Connected device (2 available)
    • macOS (desktop) • macos  • darwin-x64     • macOS 12.0.1 21A559 darwin-x64
    • Chrome (web)    • chrome • web-javascript • Google Chrome 97.0.4692.71

! Doctor found issues in 1 category.
```

</details>


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