Missing username

Description:

New Users cannot be activated or edited if Manually Approve New Users is set to True

This was evidently an issue two and three years ago. Two years later this is STILL an issue. See https://github.com/RocketChat/Rocket.Chat/issues/7037
I tried to post my comment there, but that issue is closed.

Steps to reproduce:

1. • There is no space for a username on the registration form, there is only space for a new user to provide a name.
   • Allow Username Change is set to False (I saw that as a possible remedy in issue https://github.com/RocketChat/Rocket.Chat/issues/7037)
   • Manually Approve New Users is set to True

When a user registers, the username field is left @undefined

So when I click on that user to activate it, I get a white screen (WSOD) whether I am in the Linux App or on the Webchat page. Of course, this makes it impossible to approve new users manually.

I tried setting Allow Name Change also to False, to see if that triggers a different behavior, but the result is the same.

Expected behavior:

The Username field should either be available and required at registration, which is preferable, OR it should be automatically populated at registration from information in the Name field.

Actual behavior:

So to get around the WSOD and be able to approve a new user, I have to go to Accounts and set Manually Approve New Users to False, so then I can edit and activate the user.

Server Setup Information:

• Version of Rocket.Chat Server: 3.5.2
• Operating System: Ubuntu 20.04
• Deployment Method: Snap
• Number of Running Instances: 1
• DB Replicaset Oplog: ???
• NodeJS Version: 12.16.1
• MongoDB Version: 3.6.14

Client Setup Information

• Desktop App or Browser Version: App version 2.17.11 AND/OR Firefox 80.0
• Operating System: Linux Mint 18.3

Additional context

Relevant logs:

No file or test is named in the report. Start by reproducing registration with Manually Approve New Users enabled, then trace the registration and user-activation entry points; done means a pending user receives a valid username and can be activated or edited without a white screen.