Using correct column for sorting users by Recent Sign-in

What does this MR do?

Uses current_sign_in_at instead of last_sign_in_at for sorting users by "Recent Sign-in". According to https://github.com/plataformatec/devise/blob/master/lib/devise/models/trackable.rb, last_sign_in_at points to the previous time the user logged in. The correct column to use here is current_sign_in_at as this gets updated every time a user logs in and is not set to nil when the user logs out.

Are there points in the code the reviewer needs to double check?

No

Why was this MR needed

To sort the users by "Recent Sign-in" correctly

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #26468 (moved)