Clean up promote_ultimate_features experiment

app/models/onboarding/progress.rb

...ig/feature_flags/experiment/promote_ultimate_features.yml

...cts/learn_gitlab/components/learn_gitlab_section_link.vue

...ojects/learn_gitlab/components/paid_feature_indicator.vue

...avascripts/pages/projects/learn_gitlab/constants/index.js

...ets/javascripts/pages/projects/learn_gitlab/show/index.js

ee/app/helpers/projects/learn_gitlab_helper.rb

...p/services/registrations/base_namespace_create_service.rb

ee/spec/features/registrations/combined_registration_spec.rb

...ith_trial_from_external_site_without_confirmation_spec.rb

...art_trial_from_external_site_without_confirmation_spec.rb

...gitlab/components/__snapshots__/learn_gitlab_spec.js.snap

...learn_gitlab/components/learn_gitlab_section_link_spec.js

...ges/projects/learn_gitlab/components/learn_gitlab_spec.js

...ntend/pages/projects/learn_gitlab/components/mock_data.js

...ts/learn_gitlab/components/paid_feature_indicator_spec.js

ee/spec/helpers/projects/learn_gitlab_helper_spec.rb

ee/spec/requests/registrations/groups_controller_spec.rb

...ces/registrations/import_namespace_create_service_spec.rb

...s/registrations/standard_namespace_create_service_spec.rb