Fix split policy test

- This change was made to match the change in b2d4fc8
  where the largest geometry is now inherited by the original feature when
  splitting features.
- This caused the test to fail for the 'field_unset' and 'field_ratio' attributes
  since the largest feature with the largest 'field_ratio' attribute
  also had the original 'field_unset' value and the others had an unset
  attribute

tests/src/python/test_qgsvectorlayereditutils.py

@@ -752,9 +752,9 @@ def test_split_policy_lines(self):
         self.assertCountEqual(
             attributes,
             [
-                [None, 3301.0, 302.0, 303.0, 8.664000000000001, 305.0],
+                [None, 3301.0, 302.0, 303.0, 277.53878260869567, 305.0],
+                [None, 301, 302.0, QgsUnsetAttributeValue(), 8.664000000000001, 305.0],
                 [None, 301, 302.0, QgsUnsetAttributeValue(), 17.797217391304347, 305.0],
-                [None, 301, 302.0, QgsUnsetAttributeValue(), 277.53878260869567, 305.0],
             ],
         )