Application prevents machine from shut down / restart

Describe the Bug

When trying to shut down or restart on a macOS machine, the Camunda Modeler application prevents from doing it by hanging up.

The current workaround is to manually close the application afterward.

Steps to Reproduce

1. Open Camunda Modeler, no files have to be open
2. Try to shut down or restart OS from the application menu
3. See that Camunda Modeler is not terminating

Expected Behavior

The application should terminate and the shutdown/restart should be going on.

Environment

• OS: macOS 10.15.4 / 11.2.3 (https://github.com/camunda/camunda-modeler/issues/2230)
• Camunda Modeler Version: 4.0.0-alpha.3, but also older versions (tested on 3.7, 3.3, 3.0)

Additional Resources

I attached the logs from the Modeler application after the quit was initiated

2020-05-18T08:26:48.935Z  INFO app:main asking client to allow quit
2020-05-18T08:26:48.938Z  INFO app:main quit allowed
2020-05-18T08:26:48.938Z  INFO app:main initating close of main window
2020-05-18T08:26:48.938Z  INFO app:main main window closed
2020-05-18T08:26:48.939Z  INFO app:mac-os Keeping app in the dock

See how the app is not terminating mode afterward, cf. window-all-closed handler

[nikku]

If that does not cause any side effects with the “app stays open on MacOS” behavior.

From what I understand apps remain running on MacOS until forcefully closed. We should not unbuild that feature.

[pinussilvestrus]

We do a force close in dev mode (cf. dev.js)

// make sure the app quits and does not hang
app.on('before-quit', function() {
  app.exit(0);
});

Is there a reason why we don’t do this also in production? This way we could also close all the windows gracefully as other apps do it (https://github.com/camunda/camunda-modeler/issues/1803#issuecomment-827616545) - or simply force closing.