Update Ldap style for redesigned login Page

What does this MR do and why?

This MR is meant to solve: #368915 (closed) it restyles the LDAP Login parts of sign-in-page when restyle_login_page is active.

Screenshots or screen recordings

flag off	before	after
2022-09-08_17-36-21	2022-09-08_17-32-32	2022-09-08_17-31-17

How to set up and validate locally

1. enable restyle_login_page flag
2. in your config/gitlab.yml
3. search for LDAP Settings and set enabled: true
4. go to login page

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.