Server gets immediately nuked on restart/stop, no chance to run shutdown events/hooks

It looks like we have a behaviour change in that regard from from OctoPi < 1.0.0 to OctoPi >= 1.0.0.

Example:

OctoPi 0.18.0:

2023-11-28 17:52:47,473 - octoprint.server - INFO - Shutting down...
2023-11-28 17:52:47,485 - octoprint.server - INFO - Calling on_shutdown on plugins
2023-11-28 17:52:47,489 - octoprint.events - INFO - Processing shutdown event, this will be our last event
2023-11-28 17:52:47,672 - octoprint.events - INFO - Event loop shut down
2023-11-28 17:52:47,921 - octoprint.plugins.tracking - INFO - Sent tracking event shutdown, payload: {}
2023-11-28 17:52:48,111 - octoprint.server - INFO - Goodbye!
2023-11-28 17:52:55,660 - octoprint.startup - INFO - ******************************************************************************
2023-11-28 17:52:55,663 - octoprint.startup - INFO - Starting OctoPrint 1.9.3
2023-11-28 17:52:55,665 - octoprint.startup - INFO - ******************************************************************************

OctoPi 1.0:

2023-11-28 17:58:10,696 - octoprint.plugins.github_release_patcher - INFO - Started dummy release server on http://127.0.0.1:50672
2023-11-28 17:58:10,696 - octoprint.plugins.github_release_patcher - INFO - Set Github release URL to http://127.0.0.1:50672/releases/{user}/{repo}
2023-11-28 18:01:21,363 - octoprint.startup - INFO - ******************************************************************************
2023-11-28 18:01:21,366 - octoprint.startup - INFO - Starting OctoPrint 1.9.3
2023-11-28 18:01:21,367 - octoprint.startup - INFO - ******************************************************************************

No shutdown events triggered. It looks like the systemd unit on 1.0 simply nukes away the server directly, whereas on OctoPi < 1.0 it still got a chance to cleanly shut down. That's something that needs to get looked at, but that's rather something for OctoPrint/OctoPi-UpToDate or guysoft/OctoPi.

Originally posted by @foosel in https://github.com/OctoPrint/OctoPrint/issues/4882#issuecomment-1830406813

Compare the systemd unit behavior in OctoPi versions before 1.0 with OctoPi 1.0, focusing on how restart and stop terminate the server. Reproduce the issue and inspect the shutdown logs; done means shutdown hooks and events run before the server is terminated.