Enable formatting for package:appengine

[mosuem]

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[github-actions]

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// Copyright (c) 2026, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

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Files
pkgs/timezone/example/example.dart
pkgs/timezone/test/datetime_browser_test.dart
pkgs/timezone/test/datetime_test.dart
pkgs/timezone/test/datetime_test_no_database.dart
pkgs/timezone/test/env_test.dart
pkgs/timezone/test/two_way_test.dart
pkgs/timezone/test/zicfile_test.dart
pkgs/timezone/test/zone_tab_test.dart
pkgs/timezone/tool/encode_dart.dart
pkgs/timezone/tool/encode_tzf.dart
pkgs/timezone/tool/get.dart
pkgs/timezone/tool/test_random.dart
pkgs/timezone/tool/zone_dump.dart

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