TextField magnifier is much smaller than the native Android loupe

On Android, the text selection magnifier shown by Flutter's `TextField` appears much smaller than the native Android loupe on the same device.

I can reproduce this on a Pixel 7 with Flutter 3.44.1. The same small loupe appears both in my production app from the Play Store and in the minimal Flutter app below, so this does not seem to be caused by app-specific text field configuration.

## Screenshots

Both screenshots were taken on a Pixel 7.

Play Store
Minimal Flutter app, Flutter 3.44.1

## Steps to reproduce

Run this app on Android, long-press or drag in the text field to show the text selection magnifier, and compare the loupe size with the native Android text selection loupe on the same device.

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

void main() => runApp(const MaterialApp(home: Repro()));

class Repro extends StatefulWidget {
const Repro({super.key});

@override
State createState() => _ReproState();
}

class _ReproState extends State {
late final controller = TextEditingController(text: 'Some text');

@override
void dispose() {
controller.dispose();
super.dispose();
}

@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: SizedBox(width: 320, child: TextField(controller: controller)),
),
);
}
}
```

## Expected result

The Android `TextField` magnifier should closely match the native Android text selection loupe size and visual fidelity on the same device.

## Actual result

Flutter's Android `TextField` magnifier is visibly smaller than the native Android loupe.

## Environment

- Flutter 3.44.1
- Device: Pixel 7
- Platform: Android 16