Repository: huggingface/transformers
Pull request: Fix failing `ProphetNetModelIntegrationTest`

# What does this PR do?
Fixes this failing [ProphetNetModelIntegrationTest](https://github.com/huggingface/transformers/actions/runs/22606636929/job/65500453490#step:14:2331).

<img width="2303" height="165" alt="image" src="https://github.com/user-attachments/assets/b42698b4-6ed7-4b4e-b200-2d1332ddd80a" />


Since here we are passing `skip_special_tokens=True`, special token `[X_SEP]` will be removed.
```python
generated_titles = [" ".join(tokenizer.convert_ids_to_tokens(g, skip_special_tokens=True)) for g in summary_ids]
```

## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
- [x] Did you read the [contributor guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#create-a-pull-request),
      Pull Request section?
- [ ] Was this discussed/approved via a Github issue or the [forum](https://discuss.huggingface.co/)? Please add a link
      to it if that's the case.
- [ ] Did you make sure to update the documentation with your changes? Here are the
      [documentation guidelines](https://github.com/huggingface/transformers/tree/main/docs), and
      [here are tips on formatting docstrings](https://github.com/huggingface/transformers/tree/main/docs#writing-source-documentation).
- [ ] Did you write any new necessary tests?


## Who can review?
@Rocketknight1 @vasqu

Changed files:
filename: tests/models/prophetnet/test_modeling_prophetnet.py
patch: @@ -1154,7 +1154,7 @@ def test_pretrained_checkpoint_hidden_states(self):
     @slow
     def test_cnndm_inference(self):
         model = ProphetNetForConditionalGeneration.from_pretrained("microsoft/prophetnet-large-uncased-cnndm")
-        model.config.max_length = 512
+        model.generation_config.max_length = 512
         model.to(torch_device)
 
         tokenizer = ProphetNetTokenizer.from_pretrained("microsoft/prophetnet-large-uncased-cnndm")
@@ -1176,7 +1176,7 @@ def test_cnndm_inference(self):
             input_ids, num_beams=4, length_penalty=1.0, no_repeat_ngram_size=3, early_stopping=True
         )
         EXPECTED_SUMMARIZE_512 = (
-            "us ##tc was founded by the chinese academy of sciences ( cas ) in 1958 . [X_SEP] us ##tc is listed in the"
+            "us ##tc was founded by the chinese academy of sciences ( cas ) in 1958 . us ##tc is listed in the"
             " top 16 national key universities ."
         )
         generated_titles = [
@@ -1193,10 +1193,10 @@ def test_cnndm_inference(self):
             input_ids, num_beams=4, length_penalty=1.0, no_repeat_ngram_size=3, early_stopping=True
         )
         EXPECTED_SUMMARIZE_100 = (
-            r"us ##tc was founded in beijing by the chinese academy of sciences ( cas ) in 1958 . [X_SEP] us ##tc "
+            r"us ##tc was founded in beijing by the chinese academy of sciences ( cas ) in 1958 . us ##tc "
             "'"
-            " s founding mission was to develop a high - level science and technology workforce . [X_SEP]"
-            ' establishment hailed as " a major event in the history of chinese education and science "'
+            " s founding mission was to develop a high - level science and technology workforce . "
+            'establishment hailed as " a major event in the history of chinese education and science "'
         )
         generated_titles = [
             " ".join(tokenizer.convert_ids_to_tokens(g, skip_special_tokens=True)) for g in summary_ids