Move Learn Gitlab JS to ee

What does this MR do and why?

Learn GitLab is an ee only concern. Let's move as much as we can that references it to ee.

Remove references to learn gitlab from foss invite members modal and instead only define it in the ee version.

📓 followed https://docs.gitlab.com/ee/development/ee_features.html#extend-other-js-code

How to validate locally

note basically trying to emulate feature spec steps in ee/spec/features/registrations/saas/standard_flow_just_me_creating_project_spec.rb

1. Setup to simulate SaaS and restart GDK
   • Make sure Admin > Settings > General > Sign Up Restrictions match the below (no admin approval, but hard email confirmation)
2. Enable the invite_for_help_continuous_onboarding feature flag in rails console with Feature.enable(:invite_for_help_continuous_onboarding)
3. Register as a new user.
4. Confirm email by finding the confirmation path from last User created in rails console
   • Rails.application.routes.url_helpers.user_confirmation_path(confirmation_token: User.last.confirmation_token)
5. Visit the path from the previous step.
6. You should be on the sign in page, log back in.
7. Select any 'role' and 'Just me' in the welcome form after sign up step.
8. Choose 'Create a new project'
9. Click 'Continue'
10. Fill out fields to create a group and project on the next page.
11. Click 'Create project'
12. Verify you get to the onboarding and page refreshes to provide a "Ok, let's go" button.
13. Click on "Ok, let's go" and verify you are dropped into the learn gitlab project and the celebrate modal pops up with confetti
14. Close that modal.
15. Click on the Invite your colleagues link and observe the modal.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #387662 (closed)