Repository: flutter
Issue: TextFormField.onFieldSubmitted with TextInputAction.next fails inside a GestureDetector which requestFocus
Labels: a: text input,framework,f: material design,a: error message,f: focus,has reproducible steps,found in release: 3.3,found in release: 3.6,team-design,triaged-design

## Steps to Reproduce

1. Create a `TextFormField` with a `onFieldSubmitted` and `textInputAction: TextInputAction.next`
2. Wrap the textField inside a `GestureDetector` which calls `requestFocus(FocusNode())` on a `panDowEvent`
3. Now if you tap the field, type something and press *next* on the keyboard, `onFieldSubmitted` is called
4. If you then swipe the page and try to focus on the text field again and press *next* on the keyboard, `onFieldSubmitted` is not called again

**Expected results:** <!-- what did you want to see? -->

I would expect `onFieldSubmitted` to always be called.

**Actual results:** <!-- what did you see? -->

`onFieldSubmitted` is not called after `requestFocus` on gesture event. Note this only seem to happen on `textInputAction: TextInputAction.next`.

### Example

```
import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'onSubmitted test',
      home: Page1(),
    );
  }
}

class Page1 extends StatefulWidget {
  @override
  _Page1State createState() => _Page1State();
}

class _Page1State extends State<Page1> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Page 1'),
      ),
      body: GestureDetector(
        behavior: HitTestBehavior.opaque,
        onPanDown: (_) {
          FocusScope.of(context).requestFocus(FocusNode());
        },
        child: Center(
          child: ListTile(
            title: TextFormField(
              onFieldSubmitted: (text) {
                debugPrint('onFieldSubmitted');
              },
              textInputAction: TextInputAction.next,
            ),
          ),
        ),
      ),
    );
  }
}
```

Notice how *onFieldSubmitted* is not printed after you swipe the page.

<details>
  <summary>Logs</summary>

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[log.txt](https://github.com/flutter/flutter/files/5244821/log.txt)

<!--
     Run `flutter analyze` and attach any output of that command below.
     If there are any analysis errors, try resolving them before filing this issue.
-->

```
Analyzing test_on_submitted...
No issues found! (ran in 2.0s)
```

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
[✓] Flutter (Channel dev, 1.22.0-12.0.pre, on Mac OS X 10.15.6 19G2021, locale en-GB)
    • Flutter version 1.22.0-12.0.pre at /Users/erlend/flutter
    • Framework revision a27c242b0e (7 days ago), 2020-09-11 17:46:57 -0400
    • Engine revision fee6f9e533
    • Dart version 2.10.0 (build 2.10.0-110.0.dev)


[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/erlend/Library/Android/sdk
    • Platform android-29, build-tools 29.0.2
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.7)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.7, Build version 11E801a
    • CocoaPods version 1.9.1

[✓] Android Studio (version 4.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 49.0.2
    • Dart plugin version 193.7547
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.40.0)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.8.0

[✓] Connected device (2 available)
    • Erlend (mobile) • 76dfa318a18803240a229805dd90bcb18d07fef1 • ios        • iOS 13.7
    • macOS (desktop) • macos                                    • darwin-x64 • Mac OS X 10.15.6 19G2021

• No issues found!
```

</details>