why not change the pgadmin username for Administrator Role when the auth soure is "internal"

Describe the bug
Administrator Role cloud not change the username of the authentication source is “internal”.

we see the document explation: User Management — pgAdmin 4 9.4 documentation

To Reproduce

Steps to reproduce the behavior:

1. Go to 'user managerment'
2. Click on 'edit user & username'
3. See the error : the username Grayed out, unable to edit

Expected behavior

Administrator Role can change the username of the authentication source is “internal”.

Error message

Our pgadmin user not configuration email authentication & authenticator App.
And pgadmin localhost not be connected.

Above are not the bug point, the point is as administrator login pgadmin successfully,
could not to change the username of the authentication source is “internal” from webfront.

Screenshots

N/A

Desktop (please complete the following information):

• OS: [ Linux ]
• Version: [ 9.4.0 ]
• Mode: [e.g Desktop or Server]
• Browser (if running in server mode): [e.g. chrome, safari]
• Package type: [e.g. RPM, DEB, Python, Container, etc.]

Additional context

Add any other context about the problem here.

Start at User Management and the edit user & username flow, focusing on the internal authentication source. Compare the behavior with the linked User Management documentation, reproduce the greyed-out username field, and verify that an Administrator can change the username.