Merge branch '363960-migrate-button' into 'master'

Use ButtonComponent on "previously merged commits"

See merge request !89739

app/views/projects/merge_requests/_commits.html.haml

@@ -8,7 +8,7 @@
     - if can_update_merge_request
       %p
         = _('Push commits to the source branch or add previously merged commits to review them.')
-      %button.btn.gl-button.btn-confirm.add-review-item-modal-trigger{ type: "button", data: { commits_empty: 'true', context_commits_empty: 'true' } }
+      = render Pajamas::ButtonComponent.new(variant: 'confirm', button_options: { class: 'add-review-item-modal-trigger', data: { commits_empty: 'true', context_commits_empty: 'true' } }) do
         = _('Add previously merged commits')
 - else
   %ol#commits-list.list-unstyled