[Bug] AppFlowyEditorLocalizations delegate does not support ko locale

### Bug Description

When I declare my app to support both English and Korean…
```dart
supportedLocales: [
const Locale('en'),
const Locale('ko'),
],
localizationsDelegates: [
AppFlowyEditorLocalizations.delegate,
GlobalMaterialLocalizations.delegate,
GlobalWidgetsLocalizations.delegate,
GlobalCupertinoLocalizations.delegate,
],
```

…I see this warning at runtime:

```

======== Exception caught by widgets ===============================================================
The following message was thrown:
Warning: This application's locale, ko_KR, is not supported by all of its localization delegates.

• A AppFlowyEditorLocalizations delegate that supports the ko_KR locale was not found.

The declared supported locales for this app are: en, ko, ko_KR

See https://flutter.dev/to/internationalization/ for more information about configuring an app's locale, supportedLocales, and localizationsDelegates parameters.
====================================================================================================
```

It appears that AppFlowyEditorLocalizations has no Korean translations built in, so the delegate refuses to handle ko.

I’d like to know if this is indeed just because Korean isn’t yet provided in the package, and—if so—whether I can contribute or override it by adding my own ko ARB/JSON resources.

### How to Reproduce

```dart
supportedLocales: [Locale('en'), Locale('ko')],
localizationsDelegates: [
AppFlowyEditorLocalizations.delegate,
GlobalMaterialLocalizations.delegate,
GlobalWidgetsLocalizations.delegate,
GlobalCupertinoLocalizations.delegate,
],
```

### Operating System

macOS 15.5

### AppFlowy Editor Version(s)

6.0.0

### Screenshots

_No response_

### Additional Context

_No response_