Issue Summary

Unable to delete project from trash if non-existing group is in the people section.
This only happens if a group, which is added to the respective people section of the project is deleted after the project was moved to the trash.

Steps to Reproduce

1. Add a group to the people section of a project
2. Send the project to the trash
3. Delete the respective group
4. Try to delete the project from the trash

Expected Results

Project would be deleted.

Actual Results

Project is not deleted with no error.

Workaround

1. Restore the project
2. Re-create the missing group with the same name
3. From this point, you can either remove the group from the people section of the restored project or delete the project before deleting the group