How to add ReadOnlyUsers button next to Login button on the Kibana Login page

Hi,

I am currently using Kibana v7.6 and have made some customizations to the login page. Specifically, I've added a "ReadOnlyUsers" button next to the Login button (screenshot attached). When clicked, this button automatically redirects users to a read-only dashboard (default readonly user credentials added in login_bundles.js file). I achieved this by modifying the login_bundles.js file.

However, as I plan to upgrade to Kibana v7.17, I noticed that the login_bundles.js file no longer exists. I would like to maintain a similar customization in the new version, where the "ReadOnlyUsers" button redirects users to the read-only dashboard. Could someone please guide me on how to implement this in Kibana v7.17?

Thank You!