[Bug] Error `undefined` on user deletion

Description:

Sometimes user deletion process finishes with undefined error and there is no information that user successfully deleted.

Steps to reproduce:

1. Delete user in Admin UI - Users
2. Sometimes get error undefined
3. Click Delete button in Are you sure? window
4. Get another error [error-invalid-user]

Expected behavior:

User deleted without any errors

Actual behavior:

After press Delete another time

Server Setup Information:

• Version of Rocket.Chat Server: 3.18.2
• Operating System: CentOS7
• Deployment Method: docker
• Number of Running Instances: 20
• DB Replicaset Oplog: Enabled
• NodeJS Version: 12.22.1
• MongoDB Version: 4.2.15

Client Setup Information

• Desktop App or Browser Version: Chrome 95
• Operating System: Windows 10

Additional context

In fact users seems to be deleted - I don't find that user in Admin UI on mongodb, but that edge case errors must be fixed.

Relevant logs:

Nothing special in logs

Start by reproducing deletion from Admin UI - Users using the listed server and browser setup, then trace the user-deletion request and its error handling. Compare the first undefined error with the subsequent error-invalid-user response; done means deletion reports success consistently without a misleading error.