Resolve "Allow admins to disable users ability to change profile name"

What does this MR do?

For #24605 (closed)

Screenshots

Admin can set this flag to true or false

When set to true, any regular user will not be able to edit their name from their profile: (Admins will still be able to edit their own names from the profile page)

An admin can still edit the name of any user from the admin area (and also via the API)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team