chore: Fix failing test skip decorator

PiperOrigin-RevId: 830658029

Author: matthew29tang

tests/unit/aiplatform/test_vision_models.py

@@ -773,7 +773,7 @@ def test_edit_image_with_capability_mode(self):
                     "reference_image_control_config_4"
                 ] == str(control_config)
 
-    @unittest.skip(reason="b/295946075 The service stopped supporting image sizes.")
+    @pytest.mark.skip(reason="b/295946075 The service stopped supporting image sizes.")
     def test_generate_images_requests_square_images_by_default(self):
         """Tests that the model class generates square image by default."""
         model = self._get_image_generation_model()