Option 1 – Set the following Group Policy:
Computer Configuration\Policies\Administrative Templates\Windows Components\Credential User Interface\Enumerate administrator accounts on elevation
To the following value: Disabled

Option 2 – Follow these steps to apply a MEM policy:

1. Go to the Devices-> Configuration profiles
2. To update an existing policy:
   • Click on the policy name in the list
   • In the navigation bar, click on Properties
   • Next to Configuration settings click on Edit
   • Go to step #4
3. If you’d like to create a new policy, click on the Create Policy button
   • in the side panel, choose:
     • Platform: Windows 10 and later
     • Profile Type: Administrative Templates
   • Click on Create button
   • Proceed to step #4
4. In the Configuration settings wizard step, set the following:
   • Set Computer Configuration-> Windows Components-> Credential User Interface-> Enumerate administrator accounts on elevation to Disabled
5. Complete all remaining wizard steps, review and Save policy

Option 3 – Set the following registry value:
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\CredUI\EnumerateAdministrators
To the following REG_DWORD value:
0