sct_crop_image: reorder imports
sct_crop_image: reorder imports


Former-commit-id: 7c9abccaa5fd111198dd89b8fc2d4e31aa9857bc
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox