[5.1] UI Issue in Backend on multiple MFA options

[dautrich]

Steps to reproduce the issue

1. Create a backend user with multiple MF alternatives, i.e. Passkey, TOTP, Backup codes.
2. Set dark mode.
3. Login to the backend with this user.
4. Click on button "Select a different method"

Expected result

All options on the subsequent form are completely legible.

Actual result

White font on white background:

System information (as much as possible)

J5.1.2

Additional comments

For reference, the same screenshot for light mode:

[brianteeman]

Please search for existing issues before creating a new one - especially when the existing issue is your own.

see #43448