Null reference error on quit when no SpaceNavigator was connected at all.

[cpetry]

Describe the bug I get in built applications null reference errors when I don't have a SpaceNavigator attached.

To Reproduce Steps to reproduce the behavior:

1. Build an application with this package
2. Don't attach a SpaceNavigator
3. Quit the application
4. See error

Expected behavior There should be no error.

Details (please complete the following information):

• Issue occurred while navigating [in the editor viewports, in play mode]
• Device type [e.g. SpaceNavigator, Spacemouse]
• Connection [wired or wireless]
  • OS: [e.g. Windows, MacOS]
  • SpaceNavigator Driver version [e.g. 2.0.0-beta.1]

Additional context

[PatHightree]

Thanks for fixing that, merged it 👍