Loading two differnet configs causes errors

[ianhi]

e.g. the demo config followed by real scope config will result in a crash

[fdrgsp]

I think this is not happening anymore. The only remaining issue (that does not prevent the correct loading of the cfg) is here in the MMShuttersWidget

napari-micromanager/src/napari_micromanager/_gui_objects/_shutters_widget.py

Lines 29 to 37 in 60f13ca

	if not self._mmc.getLoadedDevicesOfType(DeviceType.ShutterDevice):
	# FIXME:
	# ShuttersWidget has not been tested with an empty device label...
	# it raises all sorts of errors.
	# if we want to have a "placeholder" widget, it needs more testing.
	# empty_shutter = ShuttersWidget("")
	# self.layout().addWidget(empty_shutter)
	return

I open a different issue for this #270 .