Fix instructions regarding `npm publish` registry

What does this MR do?

Targets the GitLab registry rather than the default (NPM) registry when calling npm publish.

Screenshots

Build output:

# ... NPM Output ...
npm notice 
npm ERR! code E401
npm ERR! 401 Unauthorized - PUT https://registry.npmjs.org/@NAMESPACE%2fPACKAGENAME - You must be logged in to publish packages.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and Testing

NA

Security

NA