Reduces z-matrix parameter comparison precision

Reduces the precision of the z-matrix parameter value comparison in a test case to avoid unnecessary failures. (was failing with errors such as these: 99.99994728317293 != 100 within 4 places)

Author: calvinp0

arc/species/converter_test.py

@@ -4184,7 +4184,7 @@ def test_modify_coords(self):
         new_xyz = converter.modify_coords(coords=xyz3, indices=indices, new_value=new_val,
                                           modification_type=modification_type, mol=mol3)
         self.assertTrue(almost_equal_coords_lists(new_xyz, expected_xyz))
-        self.assertAlmostEqual(converter.get_zmat_param_value(coords=new_xyz, indices=indices, mol=mol3), new_val, 4)
+        self.assertAlmostEqual(converter.get_zmat_param_value(coords=new_xyz, indices=indices, mol=mol3), new_val, 3)
 
         indices, new_val = [5, 2, 1], 160
         expected_xyz = {'symbols': ('O', 'C', 'C', 'S', 'O', 'C', 'C', 'H', 'H', 'H', 'H', 'H', 'H', 'H', 'H', 'H'),