Add util to get package name from runtime metadata schema

Context: This will be used to obtain the corresponding package that owns the schema from a getSchemaResponse.
Flag: android.app.appfunctions.flags.enable_app_function_manager
Test: atest FrameworksAppFunctionsTests -c
Bug: 357551503
Change-Id: I80200320c228e621bdff969e7be2e28f9b63d0c7