Fix Issue with sign-text on redesigned login page

What does this MR do and why?

This MR fixes: #375290 (closed) it makes sure the signin-text on the redesigned login page is displayed even when login through password is disabled.

Screenshots or screen recordings

with Allow password authentication for the web interface

before	after

without Allow password authentication for the web interface

before	after

How to set up and validate locally

1. Log in and go to Admin > Settings > General > Sign-in Restriction
2. Add text to Sign-in text field
3. Disable Allow password authentication for the web interface
4. Save Changes
5. Open the login page in Incognito mode and see the sign-in text is not shown
6. Re-enable password authentication and see the sign-in text on login page

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

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