Confirm user button in admin area only works on "Account" tab

Summary

In !64812 (merged) we moved the Confirm user button to the header which made it available on all the tabs. Due to some missing JavaScript the Confirm user currently only works on the Account page.

Steps to reproduce

1. Login as an Admin (root user in GDK)
2. Navigate to Menu -> Admin -> Users and note the username of one of the users
3. In your terminal in the gdk/gitlab directory run bin/rails console
4. Run the following commands
   • user = User.find_by_username('<user name>')
   • user.confirmed_at = nil
   • user.save
5. Navigate to Menu -> Admin -> Users and choose that user
6. There should be a Confirm user button in the header
7. Navigate to any tab other than the Account tab and click the Confirm user button

What is the current bug behavior?

Confirm user button only works on Account tab

What is the expected correct behavior?

Confirm user button should work on all tabs

Relevant logs and/or screenshots

Possible fixes

Load required JavaScript for confirmation modal to work