Fix `Remember me` omniauth

What does this MR do and why?

In the sign-in page, the ID of the Remember me checkbox element was duplicated. The same ID, remember_me, was used for the main login (upper section) and the omniauth logins (lower section). This created a couple of undesired side-effects:

1. Selecting on the lower Remember me checkbox, checked the upper checkbox (main login).
2. More importantly, the Remember me was broken because it didn't add the parameter remember_me=1 to the action path of the form surrounding the ommiauth logins.

This commit fixes the issue by replacing the remember_me ID to a more specific name, remember_me_omniauth, for the omniauth logins.

Closes #385419 (closed)

Screenshots or screen recordings

N/A

How to set up and validate locally

1. Enable LDAP login: https://gitlab.com/gitlab-org/gitlab-development-kit/-/blob/main/doc/howto/ldap.md
2. Go to the sign-in page: https://gdk.test:3443/users/sign_in
3. Toggle the lower Remember me checkbox.
4. The upper Remember me checkbox should remain unchecked.
5. A remember_me=1 parameter should be added to the <form>'s action attribute connected to the omniauth buttons.

Screen_Recording_2023-03-21_at_12.05.27

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