Remove duplicate error types in admin service
This PR removes the duplicate error types defined in the `admin` service and use the ones defined in `libapi`.

This PR needs the following PR to be merged first:
- [x] #1945

Otherwise, see "services/admin / quality / code-quality": https://github.com/huggingface/datasets-server/actions/runs/6433158237/job/17469627449
```
Because admin depends on libapi (0.1.0) @ file:///home/runner/work/datasets-server/datasets-server/libs/libapi which depends on starlette (^0.28.0), starlette is required.
So, because admin depends on starlette (^0.27.0), version solving failed.
```
Remove duplicate error types in admin service: This PR removes the duplicate error types defined in the `admin` service and use the ones defined in `libapi`.

This PR needs the following PR to be merged first:
- [x] #1945

Otherwise, see "services/admin / quality / code-quality": https://github.com/huggingface/datasets-server/actions/runs/6433158237/job/17469627449
```
Because admin depends on libapi (0.1.0) @ file:///home/runner/work/datasets-server/datasets-server/libs/libapi which depends on starlette (^0.28.0), starlette is required.
So, because admin depends on starlette (^0.27.0), version solving failed.
```