test(aliby): fix forgotten dimension

WHY IS THIS CHANGE NEEDED?:
- https://git.ecdf.ed.ac.uk/swain-lab/aliby/aliby/-/jobs/56781 failed

REFERENCES:
- issue #53

tests/aliby/pipeline/test_image.py

@@ -10,7 +10,7 @@ tiler_parameters = {"tile_size": 117, "ref_channel": "Brightfield", "ref_z": 0}
 sample_da = da.from_array(np.array([[1, 2], [3, 4]]))
 # Make it 5-dimensional
 sample_da = da.reshape(
-    sample_da, (1, 1, sample_da.shape[-2], sample_da.shape[-1])
+    sample_da, (1, 1, 1, sample_da.shape[-2], sample_da.shape[-1])
 )
 
 
@@ -34,6 +34,6 @@ def test_pad_array(sample_da, dim, n_empty_slices):
     ]
 
     # Checks that original image array is there and is at the last index
-    assert np.array_equal(padded_da.compute()[ix], sample_da)
+    assert np.array_equal(padded_da.compute()[ix], sample_da.compute()[0])
     # Checks that the additional axis is extended correctly
     assert padded_da.compute.shape[dim] == n_empty_slices + 1