multi sample cropping transforms to inherit MultiSampleTrait

[wyli]

Is your feature request related to a problem? Please describe.
transforms should specify whether multiple samples will be returned with

MONAI/monai/transforms/transform.py

Lines 174 to 179 in 9ddb14c

	class MultiSampleTrait:
	"""
	An interface to indicate that the transform has the capability to return multiple samples
	given an input, such as when performing random crops of a sample. This interface can be
	extended from by people adapting transforms to the MONAI framework as well as by implementors
	of MONAI transforms.

this is useful for #5711