Fix DeBERTa token_type_ids
# What does this PR do?

This PR fixes #15735. It changes the behavior of `DebertaTokenizer` and `DebertaTokenizerFast` when passing pair inputs. Before, the token type IDs were all `0`. This PR changes this so that the `token_type_id`s for the tokens of the second sentence are `1`. 

It also adds a test case to test this behavior (`DebertaTokenizationTest.test_token_type_ids`). Failed before, passes now.

## Before submitting
- [x] Did you read the [contributor guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      Pull Request section?
- [x] 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. https://github.com/huggingface/transformers/issues/15735
- [x] 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).
- [x] Did you write any new necessary tests?


## Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

@LysandreJik?
_The documentation is not available anymore as the PR was closed or merged._<|||||>Great, thanks for looking into this! I also checked Microsoft's implementation and [it looks like](https://github.com/microsoft/DeBERTa/blob/c558ad99373dac695128c9ec45f39869aafd374e/DeBERTa/deberta/deberta.py#L77) they use `1` for sentence B as well 😊