fix deflection test

Author: Niek Wielders

test_autogalaxy/profiles/mass/dark/test_cnfw.py

@@ -7,7 +7,7 @@ def test__deflections_yx_2d_from():
     cnfw = ag.mp.cNFW(centre=(0.0, 0.0), kappa_s=0.01591814312464436, scale_radius=0.36, core_radius=0.036)
 
     deflection_2d = cnfw.deflections_yx_2d_from(grid=ag.Grid2DIrregular([[1.0, 0.0]]))
-    deflection_r = np.sqrt(deflection_2d[0]**2 + deflection_2d[1]**2)
+    deflection_r = np.sqrt(deflection_2d[0, 0]**2 + deflection_2d[0, 1]**2)
 
     assert deflection_r == pytest.approx(0.006034319441107217, 1.0e-8)