chore: add publish dry run test stage

[FezVrasta]

PR checklist

• [x] I have followed the "Committing and publishing" guidelines;
• [x] I have added unit tests to cover my changes;
• [ ] I updated the documentation and examples accordingly; N/A

Changes description

This aims to add a new CI stage where we publish the packages to a "fake" npm registry to make sure the whole publishing step works.

This should prevent future publish issues from happening.

Affected packages

• N/A