Issue 429094  merged all non-real implementation of SessionManagerClient into FakeSesisionManagerClient.

This merge will let SessionManagerStubClient observers start to receive notifications. It triggers SoundsManager::Play during this observer emission.

AudioStreamHandler will use its stored pointer to AudioManager (stored during initialization, which stores the real one) instead of AudioManager::Get() AudioManager (which is the mock one created for test).

KioskVirtualKeyboardTestSoundsManagerTestImpl is created to workaround AudioStreamHandler intentially keeping copy of pointer to real AudioManager.


But a better solution could be:
1) move initialization of MockAudioManager into SetUp
2) modify AudioManager to let real AudioManager not overriding MockAudioManager if already initialized.