Fix CI for `PegasusX`
# What does this PR do?

- `PegasusXGlobalLocalAttention` returns attentions as dictionary:

  ```python
        if output_attentions:
            attn_probs = {"global": global_attn_probs, "local": local_attn_probs}
        else:
            attn_probs = None
  ```
  Skip this test to avoid failure [here](https://github.com/huggingface/transformers/actions/runs/2986602848/jobs/4788460628).

- Fix `PegasusXModelIntegrationTests` by updating the expected values + proper checkpoint
_The documentation is not available anymore as the PR was closed or merged._