Fix cost condition in DetrHungarianMatcher and YolosHungarianMatcher to allow zero-cost
# What does this PR do?

Fixes costs condition in DetrHungarianMatcher and YolosHungarianMatcher. In https://github.com/huggingface/transformers/pull/16720 a bug was introduced while switching from asserts to conditions. Currently, any zero-cost will result in a ValueError:

```python
if class_cost == 0 or bbox_cost == 0 or giou_cost == 0:
    raise ValueError("All costs of the Matcher can't be 0")
```

## 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#start-contributing-pull-requests),
      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?

@LysandreJik @sgugger based on reviewers of previous PR https://github.com/huggingface/transformers/pull/16720.

_The documentation is not available anymore as the PR was closed or merged._<|||||>This looks reasonable given the error message! cc @NielsRogge 