[Bug]: Java: Generated samples have a "is not used" warning

### Describe the bug

After generating samples, all samples have a warning like this:

### Reproduction

I used this tsplocattion:
```
directory: specification/purview/data-plane/datamap
commit: 0c932f4a1e126784161397209484678f3adda2f6
repo: Azure/azure-rest-api-specs
```

applied to the purview datamape package (just call tspclient update)

### Checklist

- [x] Follow our [Code of Conduct](https://github.com/microsoft/typespec/blob/main/CODE_OF_CONDUCT.md)
- [x] Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
- [x] Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/Microsoft/typespec/discussions).
- [x] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.