Do not invite deleted accounts to the project

Typically, user accounts are identified uniquely by their email. However, this only applies to active accounts. When an account is deleted, Rodauth changes its status to '3:deleted' and allows the creation of a new account with the same email. Therefore, when we select a user solely by email, we might retrieve a deleted account. To prevent this, we need to exclude deleted accounts. Some of our customers have already encountered this issue.