Migrate pipeline setting checkbox to Pajamas design system

Changelog: changed

app/views/projects/edit.html.haml

@@ -33,7 +33,7 @@
   .settings-content
     = render_if_exists 'shared/promotions/promote_mr_features'
 
-    = form_for @project, html: { multipart: true, class: "merge-request-settings-form js-mr-settings-form" }, authenticity_token: true do |f|
+    = gitlab_ui_form_for @project, html: { multipart: true, class: "merge-request-settings-form js-mr-settings-form" }, authenticity_token: true do |f|
       %input{ name: 'update_section', type: 'hidden', value: 'js-merge-request-settings' }
       = render 'projects/merge_request_settings', form: f
       = f.submit _('Save changes'), class: "btn gl-button btn-confirm rspec-save-merge-request-changes", data: { qa_selector: 'save_merge_request_changes_button' }

ee/app/views/projects/_merge_pipelines_settings.html.haml

 - return unless merge_pipelines_available?
 
 .form-check.builds-feature
-  = form.check_box :merge_pipelines_enabled, class: 'form-check-input js-merge-options-merge-pipelines', data: { qa_selector: 'merged_results_pipeline_checkbox' }
-  = form.label :merge_pipelines_enabled, class: 'form-check-label' do
-    = s_('ProjectSettings|Enable merged results pipelines')
-    .text-secondary.mb-2
   - configuring_pipelines_for_merge_requests_help_link_url = help_page_path('ci/pipelines/merge_request_pipelines.md', anchor: 'prerequisites')
   - configuring_pipelines_for_merge_requests_help_link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe % { url: configuring_pipelines_for_merge_requests_help_link_url }
-      = s_('ProjectSettings|When merge request pipelines are enabled in the CI/CD configuration file, pipelines validate the combined results of the source and target branches. %{link_start}How to configure merge request pipelines?%{link_end}').html_safe % { link_start: configuring_pipelines_for_merge_requests_help_link_start, link_end: '</a>'.html_safe }
+  = form.gitlab_ui_checkbox_component :merge_pipelines_enabled,
+    s_('ProjectSettings|Enable merged results pipelines'),
+    checkbox_options: { data: { qa_selector: 'merged_results_pipeline_checkbox' }, class: 'js-merge-options-merge-pipelines' },
+    help_text: s_('ProjectSettings|When merge request pipelines are enabled in the CI/CD configuration file, pipelines validate the combined results of the source and target branches. %{link_start}How to configure merge request pipelines?%{link_end}').html_safe % { link_start: configuring_pipelines_for_merge_requests_help_link_start, link_end: '</a>'.html_safe }

qa/qa/ee/page/project/settings/merge_request.rb

@@ -29,7 +29,7 @@ module QA
             end
 
             def click_pipelines_for_merged_results_checkbox
-              check_element(:merged_results_pipeline_checkbox)
+              check_element(:merged_results_pipeline_checkbox, true)
             end
 
             def click_merge_trains_checkbox