Log the suspend blocker ID in DefaultStateMachine

Logging the ID of the suspend blocker from DefaultStateMachine made it easier for me to determine the client that was holding the PinePhone awake. You can do it by finding the DefaultStateMachine's log line for disallow_suspend, then searching for the corresponding allow_suspend call. The log lines around disallow_suspend help find the cause of the hanging suspend blocker.

Unfortunately, the suspend IDs in practice are numeric rather than descriptive as they are in the test. But making this change still helped my troubleshooting.