Integrate cropping into the same code paths

[multimeric]

Currently we have two entirely different code paths for cropping and non-cropping workflow. However, we could reduce a lot of code, and simplify maintenance by not doing this:

napari_lattice/core/lls_core/models/lattice_data.py

Lines 444 to 453 in 03da202

	if self.cropping_enabled:
	return ImageSlices(
	lattice_data=self,
	slices=self._process_crop()
	)
	else:
	return ImageSlices(
	lattice_data=self,
	slices=self._process_non_crop()
	)

This isn't a high priority, but just wanted to note it down somewhere.