Fix formatting of welcome screen for external users

What does this MR do?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/45797 - Fixes bad formatting of welcome screen for external users.

Steps to show this view:

1. Register as a new user
2. Logout
3. Login as root
4. Go to /admin/users
5. Find the newly registered user, hit edit
6. Select External user
7. Hit save
8. Logout
9. Login as the new user
10. Here you should see only 3 options (see screenshots below)

Screenshots

Before	After

Breakpoints

External users	Non-external users
breakpoints	breakpoints-non-external

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios.
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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

Closes #45797 (moved)