Review and update integration tests for Tizen plugins

[seungsoo47]

Background / Purpose

The integration tests of several Tizen plugins have drifted from their
upstream counterparts or only cover a thin slice of the API. This issue tracks
a systematic pass to bring each testable plugin's integration tests up to date,
so that they reflect the current behavior and are actually runnable on Tizen
devices/emulators.

Scope (per plugin)

• Identify the upstream package and the exact version the Tizen plugin targets.
• For plugins that wrap an upstream package: port the test cases from that
  upstream version that can actually run on Tizen, excluding platform-specific
  cases (Android/iOS/macOS-gated) that don't apply, and consolidate them into
  the single example/integration_test/<plugin>_test.dart.
• For Tizen-specific plugins (or where upstream tests don't apply): add
  regression tests over the public API.
• Validate on a Tizen device and/or emulator.

Target plugins (testable in .github/recipe.yaml)

• audioplayers — [audioplayers] Update integration tests to upstream v6.6.0 #1036
• connectivity_plus — already covered; no Tizen-runnable cases to add
• device_info_plus — [device_info_plus] Add regression integration tests #1038
• flutter_secure_storage
• flutter_tts
• integration_test
• keyboard_detection
• messageport
• package_info_plus
• path_provider
• shared_preferences
• sqflite
• tizen_app_manager
• tizen_audio_manager
• tizen_bundle
• tizen_package_manager
• tizen_rpc_port
• tizen_window_manager
• url_launcher
• wakelock_plus

Notes

• Validation runs on tv and/or common targets via flutter-tizen drive.