Repository: flutter
Issue: Unable to use validator along with error widget in TextFormField.
Labels: a: text input,framework,a: error message,has reproducible steps,P2,has partial patch,found in release: 3.13,found in release: 3.14,team-text-input

### Is there an existing issue for this?

- [X] I have searched the [existing issues](https://github.com/flutter/flutter/issues)
- [X] I have read the [guide to filing a bug](https://flutter.dev/docs/resources/bug-reports)

### Steps to reproduce

1. Implement Form and TextFormField
2. Add a validator for TextFormField
3. Add error widget for TextFormField

### Expected results

Expected result is that I am able to use both validator and error widget together in a textformfield

### Actual results

An error is thrown:
```Declaring both error and errorText is not supported.```


### Code sample

```dart
import 'package:flutter/material.dart';
import 'package:form_field_validator/form_field_validator.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final _formKey = GlobalKey<FormState>();

  @override
  Widget build(BuildContext context) {
    var validator = MultiValidator([
      RequiredValidator(errorText: 'This field is required'),
    ]);
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Container(
          child: Form(
            key: _formKey,
            child: Column(
              children: [
                TextFormField(
                  validator: validator,
                  decoration: InputDecoration(
                    contentPadding: EdgeInsets.zero,
                    border: const OutlineInputBorder(),
                    hintText: 'Hint Text',
                    error: Transform.translate(
                        offset: const Offset(-10, 0),
                        child: const Text('Error Text')),
                  ),
                ),
                ElevatedButton(
                  onPressed: () {
                    // Validate returns true if the form is valid, or false otherwise.
                    if (_formKey.currentState!.validate()) {
                      // If the form is valid, display a snackbar. In the real world,
                      // you'd often call a server or save the information in a database.
                      ScaffoldMessenger.of(context).showSnackBar(
                        const SnackBar(content: Text('Processing Data')),
                      );
                    }
                  },
                  child: const Text('Submit'),
                ),
              ],
            ),
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: null,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

```

### Screenshots or Video

![image](https://github.com/flutter/flutter/assets/114712929/341ec975-1db5-410c-99db-06f988076189)


### Logs

<details><summary>Logs</summary>

```console
[Paste your logs here]
```

</details>


### Flutter Doctor output

<details><summary>Doctor output</summary>

```console
[✓] Flutter (Channel stable, 3.13.1, on macOS 13.2.1 22D68 darwin-arm64, locale en-SG)
    • Flutter version 3.13.1 on channel stable at /Users/jonathanooikw/Documents/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision e1e47221e8 (7 days ago), 2023-08-22 21:43:18 -0700
    • Engine revision b20183e040
    • Dart version 3.1.0
    • DevTools version 2.25.0

[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
    • Android SDK at /Users/jonathanooikw/Library/Android/sdk
    • Platform android-34, build-tools 33.0.0
    • Java binary at: /Applications/Android Studio 2.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b802.4-9586694)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 14.2)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 14C18
    • CocoaPods version 1.12.1

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2021.2)
    • 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 11.0.12+0-b1504.28-7817840)

[✓] Android Studio (version 2022.2)
    • Android Studio at /Applications/Android Studio 2.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 17.0.6+0-17.0.6b802.4-9586694)

[✓] IntelliJ IDEA Community Edition (version 2022.3.2)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • 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

[✓] VS Code (version 1.79.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension can be installed from:
      🔨 https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

```

</details>