publish: do not copy when run with --dry-run

What

Fix a small problem with the release extended tests.

Ex: https://gitlab.com/tezos/tezos/-/jobs/10780512458

in this job has two problems:

• The first, since it's a dry run, we should not copy anything ( first commit )
• The second, associate to the token ( second commit ).

Why

How

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR