Fix korean cupertino datepicker datetime order (flutter#163850)

Currently, in the Korean locale (`ko`), the `CupertinoDatePicker`
displays the time in the order of `hour : minute : AM/PM`.
However, the correct format for Korean conventions is `AM/PM : hour :
minute`.

This PR modifies the `CupertinoDatePicker` to display the time in the
correct order when the Korean locale is used.

## Changes  
- Updated the time display order for the Korean (`ko`) locale in
`CupertinoDatePicker`.
  - Previous format: `hour : minute : AM/PM`  
  - Updated format: `AM/PM : hour : minute`

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

Author: chul0061

AUTHORS

@@ -132,3 +132,4 @@ dy0gu <[email protected]>
 Albert Wolszon <[email protected]>
 Mohammed Chahboun <[email protected]>
 Abdessalem Mohellebi <[email protected]>
+Jin Jeongsu <[email protected]>

packages/flutter_localizations/lib/src/l10n/cupertino_ko.arb

@@ -4,7 +4,7 @@
   "datePickerMinuteSemanticsLabelOne": "1분",
   "datePickerMinuteSemanticsLabelOther": "$minute분",
   "datePickerDateOrder": "ymd",
-  "datePickerDateTimeOrder": "date_time_dayPeriod",
+  "datePickerDateTimeOrder": "date_dayPeriod_time",
   "anteMeridiemAbbreviation": "오전",
   "postMeridiemAbbreviation": "오후",
   "todayLabel": "오늘",

packages/flutter_localizations/lib/src/l10n/generated_cupertino_localizations.dart

@@ -8182,7 +8182,7 @@ class CupertinoLocalizationKo extends GlobalCupertinoLocalizations {
   String get datePickerDateOrderString => 'ymd';
 
   @override
-  String get datePickerDateTimeOrderString => 'date_time_dayPeriod';
+  String get datePickerDateTimeOrderString => 'date_dayPeriod_time';
 
   @override
   String? get datePickerHourSemanticsLabelFew => null;

packages/flutter_localizations/test/cupertino/translations_test.dart

@@ -287,6 +287,20 @@ void main() {
     expect(localizations.datePickerDayOfMonth(1), '1日');
     expect(localizations.datePickerDayOfMonth(1, 2), '周二 1日');
   });
+
+  testWidgets('Test correct time order for CupertinoDatePicker in Korean locale', (
+    WidgetTester tester,
+  ) async {
+    const Locale locale = Locale('ko');
+    expect(GlobalCupertinoLocalizations.delegate.isSupported(locale), isTrue);
+
+    final CupertinoLocalizations localizations = await GlobalCupertinoLocalizations.delegate.load(
+      locale,
+    );
+
+    expect(localizations, isA<CupertinoLocalizationKo>());
+    expect(localizations.datePickerDateTimeOrder, DatePickerDateTimeOrder.date_dayPeriod_time);
+  });
 }
 
 class _FakeEditableText extends EditableText {