[1.0.2e] Ability to delete gourdlets: fixed an edge case bug

Issues fixed: Ghost gourdlet named "Null"

In my previous patch, I added the ability to delete gourdlets. I did not realize that an issue would arise when you try to delete a gourdlet that is already included in a building's guest list. This patch fixes the issue.

If anyone ran into this issue and got to a corrupt savefile, please feel free to reach out to me directly on discord and I will try to salvage your savefile!