Invalidate recognition token if model is stopped

If recognition is not active after receiving an event, invalidate the
recognition token.

Bug: 236826280
Bug: 275080257
Test: SoundTriggerManagerTest#
    testStartTriggerStopRecognitionRace_doesNotFail
Change-Id: I070e7daf5af3dff30491ec9c387b7452cb2b9642