1. Use flag to control the UI migration
2. Create language_and_region_settings.xml for new UI migration.
Bug: 379962955
Flag: com.android.settings.flags.regional_preferences_api_enabled
Test: check hsv and atest LanguagePreferenceControllerTest
Change-Id: If8d2303a2a3061231e69d1a45ad432c061da3545
- Moved the Voice Input setting from Digital assistant app to Languages & input.
- Bundled Voice Input and Text-to-speech settings together under Speech
category.
Bug: 218609449
Test: refactoring CL. Existing unit tests still pass.
Change-Id: I3107a410ed35685f5f1081cbe448b105b5c79c24