Add feature specs for the Experience Level page

- Add an example group for the introductory content
- Add an example group for the "novice" option
- Add an example group for the "experienced" option

spec/features/registrations/experience_level_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Experience level screen' do
+  let_it_be(:user) { create(:user) }
+  let_it_be(:group) { create(:group) }
+
+  before do
+    group.add_owner(user)
+    gitlab_sign_in(user)
+    stub_experiment_for_user(onboarding_issues: true)
+    visit users_sign_up_experience_level_path(namespace_path: group.to_param)
+  end
+
+  subject { page }
+
+  it 'shows the intro content' do
+    is_expected.to have_content('Hello there')
+    is_expected.to have_content('Welcome to the guided GitLab tour')
+    is_expected.to have_content('What describes you best?')
+  end
+
+  it 'shows the option for novice' do
+    is_expected.to have_content('Novice')
+    is_expected.to have_content('I’m not very familiar with the basics of project management and DevOps')
+    is_expected.to have_content('Show me everything')
+  end
+
+  it 'shows the option for experienced' do
+    is_expected.to have_content('Experienced')
+    is_expected.to have_content('I’m familiar with the basics of project management and DevOps')
+    is_expected.to have_content('Show me more advanced stuff')
+  end
+end