deploy_packaging flow runs uninstall_packaged_incremental with wrong package name

[davisagli]

It uses project__package__name but should use project__package__name_managed if provided

[jlantz]

I'm also open to discussing dropping project__package__name_managed which was only used for NPSP. We originally developed as "Cumulus" but wanted to use a more formal name in the packaging org. At the time, we were using DE orgs for everything (before scratch orgs were an option) and renaming the package in all the orgs we were using seemed daunting. Now almost all dev work is done in scratch orgs so that is less of a concern.