This way third parties can use PX4FirmwarePlugin as base class and
override as needed

Convert bool settings to SettingsFact

Use component id from heartbeat

Change in visibility was causing combo box contents to reset. Visible
goes to false even when you move away from Plan view, not just when the
combo is unused.

- Incorrect signaling causing dirty but to be incorrect
- Remove all not working
- Min fence point count incorrect