A "dry run" for uploading a package means that the uploaded package goes through every validation step but in the end isn't stored in the database. It is a "simulated run". However, it is necessary that the dry run is performed via the backend to make sure that all the requirements of the backend for uploading the package are met.

We could optionally include verification of the token. If the token is provided, it will be validated. If it is missing, only the package will be validated without the token.

Instead of a success message like "Upload successful.", a message like "Dry run successful." should be returned. In case a validation step failes, the same error message would be returned as if it was an actual upload attempt.