Refactor: Improve DeviceStateAppFunctionService modularity.

This CL splits the monolithic `DeviceStateAppFunctionService` into:

- `AbstractDeviceStateAppFunctionService`: Base service providing the execution flow and common setup.
- `DeviceStateAggregator`: Orchestrates multiple providers and decorators.
- Providers: `CatalystStateProvider` and `AndroidApiStateProvider`, responsible for specific data sources.
- Common classes and interfaces:
    - DeviceStateProvider: Interface to extract the state from a given source.
    - DeviceStateProviderResult: Data class to contain the output of DeviceStateProvider.
    - AggregatedDeviceState: Data class to contain the aggregated state from the providers before decorators.

This is a pure refactoring CL, it doesn't introduce any new functionality.

Change-Id: I403688c308170728597b8ea636736b80778d0804
Flag: com.android.settings.flags.device_state
Bug: 418989714
14 files changed