fix: let preferUnplugged override pkg.conditions

[jonaskuske]

What's the problem this PR addresses?

fix #4749

How did you fix it?

Check manifest.preferUnplugged before checking pkg.conditions so it takes precedence

Checklist

• [x] I have read the Contributing Guide.

• [ ] I have set the packages that need to be released for my changes to be effective.

• [x] I will check that all automated PR checks pass before the PR gets reviewed.