Abstract FutureAppSearchSession

Context: This is to make writing the test much easier for other dependent classes like the syncer.
Flag: android.app.appfunctions.flags.enable_app_function_manager
Test: atest FrameworksAppFunctionsTests -c
Bug: 357551503
Change-Id: I853ab02013c98d395ffd1e02f1f163d0677b4fd4
5 files changed