Re-inviting user is not re-sending invitation email

Summary

Re-inviting users in Service Desk is not causing an email to be resent or giving any warnings. That is causing confusion, as users are using a tool that should generate an email, but doesn't.

Also, there's nothing in the documentation saying what should happen when customers are invited again.

Steps to Reproduce

1. Go to the 'Customers' page in a Service Desk
2. Invite a customer, by clicking 'Invite', enter an email and click 'Send invites'
   • The invite will be sent
3. Do the same process again with the same email address

Expected Results

Either a new invite email is send (if this process was done twice, is most likely because the first one didn't work) or warn the user that a customer with that email already exists and no email will be sent.

Actual Results

No email is sent and the invitation is silently ignored.

Workaround

1. Delete the created user in User Management
2. Invite it again