Enable rescaling when resample=False

[jeskowagner]

I think there was some back and forth about the interaction of diameter, resample and the resize-ing happening under the hood. This meant that masks are sometimes returned with dimensions different to the input.

import cellpose
import cellpose.models
import numpy as np

img = np.random.rand(100,100)
model = cellpose.models.CellposeModel()

masks, _, _ = model.eval(img, diameter=10, resample=False)
print(masks.shape)
#> (300, 300) # <- this is the issue

# When using resample=True the dimensions are as expected
masks, _, _ = model.eval(img, diameter=10, resample=True)
print(masks.shape)
#> (100, 100)

[mrariden]

Thanks @jeskowagner for pointing this out. The fix is in dynamics.py:resize_and_compute_masks() which I implemented in #1438