Cleanup optional trial phone number experiment

This was an experiment which didn't reach signicance

ee/app/views/trials/new.html.haml

 - page_title _('Start your Free Gold Trial')
 - glm_params = { glm_source: params[:glm_source], glm_content: params[:glm_content] }
-- phone_number_required = Feature.disabled?(:trial_form_phone_optional, current_user)
-- phone_number_label = phone_number_required ? _('Telephone number') : _('Telephone number (Optional)')
 
 %h3.center.pt-6
   = _('Start your Free Gold Trial')
@@ -25,8 +23,8 @@
     = label_tag :company_size, _('Number of employees'), for: :company_size, class: 'col-form-label'
     = select_tag :company_size, company_size_options_for_select(params[:company_size]), include_blank: true, class: 'select2', required: true
   .form-group
-    = label_tag :phone_number, phone_number_label, for: :phone_number, class: 'col-form-label'
-    = text_field_tag :phone_number, params[:phone_number], class: 'form-control', required: phone_number_required
+    = label_tag :phone_number, _('Telephone number'), for: :phone_number, class: 'col-form-label'
+    = text_field_tag :phone_number, params[:phone_number], class: 'form-control', required: true
   .form-group
     = label_tag :number_of_users, _('How many users will be evaluating the trial?'), for: :number_of_users, class: 'col-form-label'
     = number_field_tag :number_of_users, params[:number_of_users], class: 'form-control', required: true, min: 1

ee/config/feature_flags/development/trial_form_phone_optional.yml

----
-name: trial_form_phone_optional
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/24449
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/224606
-milestone: '13.0'
-type: development
-group: group::conversion
-default_enabled: false

ee/spec/features/trials/capture_lead_spec.rb

@@ -12,38 +12,12 @@ RSpec.describe 'Trial Capture Lead', :js do
   end
 
   context 'when user' do
-    let(:trial_form_phone_optional_feature_enabled) { false }
-
     before do
-      stub_feature_flags(trial_form_phone_optional: trial_form_phone_optional_feature_enabled)
-
       visit new_trial_path
 
       wait_for_requests
     end
 
-    context 'phone number is optional' do
-      let(:trial_form_phone_optional_feature_enabled) { true }
-
-      context 'without phone number' do
-        it 'proceeds to the next step' do
-          expect_any_instance_of(GitlabSubscriptions::CreateLeadService).to receive(:execute) do
-            { success: true }
-          end
-
-          fill_in 'company_name', with: 'GitLab'
-          select2 '1-99', from: '#company_size'
-          fill_in 'number_of_users', with: '1'
-          select2 'US', from: '#country_select'
-
-          click_button 'Continue'
-
-          expect(page).not_to have_css('flash-container')
-          expect(current_path).to eq(select_trials_path)
-        end
-      end
-    end
-
     context 'enters valid company information' do
       before do
         expect_any_instance_of(GitlabSubscriptions::CreateLeadService).to receive(:execute) do

locale/gitlab.pot

@@ -26682,9 +26682,6 @@ msgstr ""
 msgid "Telephone number"
 msgstr ""
 
-msgid "Telephone number (Optional)"
-msgstr ""
-
 msgid "Template"
 msgstr ""