Update test_quadratic.py

For an unknown reason, the test was 3D for a long time, but it should have been 2D

Author: rolfjl

tests/test_quadratic.py

@@ -41,5 +41,5 @@ def test_mod(temp_examples_dir: PosixPath):
     finally:
         os.chdir(old)
 
-    np.testing.assert_array_almost_equal(state, [0.5, 0.5, 0.5], decimal=1)
+    np.testing.assert_array_almost_equal(state, [0.5, 0.5], decimal=1)
     np.testing.assert_array_almost_equal(obj, [0.0], decimal=0)