Use Pajamas button component for button in two_factor_otp.html.haml

What does this MR do and why?

Migrate buttons in app/views/admin/sessions/_two_factor_otp.html.haml to pajamas component.

It's a part of Pajamas adoption project

Changed according to migration guide available in next epic: &8153

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Before	After

How to set up and validate locally

Covered by spec/features/admin/admin_mode/login_spec.rb

You can add some delay here https://gitlab.com/gitlab-org/gitlab/-/blob/e37255208efbc2899e016768516913fa5f4afb76/spec/features/admin/admin_mode/login_spec.rb#L30 to verify the button sleep 120

WEBDRIVER_HEADLESS=false bin/rspec spec/features/admin/admin_mode/login_spec.rb:20

Related to #416034 (closed)