Update tests.py
Update tests.py

we switched the two versions of testing `pcv.visualize.clustered_contours`, but the output image was still only getting stored by the instance where `bounding=False`. So I updated which instance of the function being called will store out data that gets tested in the assertion.
stiphyMT/plantcv,danforthcenter/plantcv,stiphyMT/plantcv,danforthcenter/plantcv,stiphyMT/plantcv,danforthcenter/plantcv