This fixes a spurious warning message:

```
Type application/netcdf is already registered as a variant of
application/netcdf.
```

mime-types diff: https://my.diffend.io/gems/mime-types/3.4.1/3.5.1
History: https://github.com/mime-types/ruby-mime-types/blob/main/History.md

mime-types-data diff:
https://my.diffend.io/gems/mime-types-data/3.2022.0105/3.2023.1003
History:
https://github.com/mime-types/mime-types-data/blob/main/History.md

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/369364

Changelog: fixed