fix: baseline project ID default to undefined + refactor

[lili2311]

• [ ] Tests written and linted ℹ︎
• [ ] Documentation written ℹ︎
• [ ] Commit history is tidy ℹ︎

What this does

Ensure baseline project id defaults to undefined not ''

[aarlaud]

:tada: This PR is included in version 1.7.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: