Add feature spec for retrying Let's Encrypt

Also fix view to show `in progress` callout if certificate
is user provided, and show `failed` warning ever if we
have the certificate

app/views/projects/pages_domains/_lets_encrypt_callout.html.haml

 - if @domain.enabled?
-  - if @domain.auto_ssl_enabled && !@domain.certificate
+  - if @domain.auto_ssl_enabled
     - if @domain.show_auto_ssl_failed_warning?
       .form-group.border-section.js-shown-if-auto-ssl{ class: ("d-none" unless auto_ssl_available_and_enabled) }
         .row
@@ -10,7 +10,7 @@
                 = _("Something went wrong while the obtaining Let's Encrypt certificate.")
               .row.mx-0.mt-3
                 = link_to s_('GitLabPagesDomains|Retry'), retry_auto_ssl_project_pages_domain_path(@project, @domain), class: "btn btn-sm btn-grouped btn-warning", method: :post
-    - else
+    - elsif !@domain.certificate_gitlab_provided?
       .form-group.border-section.js-shown-if-auto-ssl{ class: ("d-none" unless auto_ssl_available_and_enabled) }
         .row
           .col-sm-10.offset-sm-2

spec/features/projects/pages_lets_encrypt_spec.rb

@@ -85,6 +85,22 @@ describe "Pages with Let's Encrypt", :https_pages_enabled do
     end
   end
 
+  context "when we failed to obtain Let's Encrypt certificate", :js do
+    let(:domain) do
+      create(:pages_domain, auto_ssl_enabled: true, auto_ssl_failed: true, project: project)
+    end
+
+    it 'user can retry obtaining certificate' do
+      visit project_pages_domain_path(project, domain)
+
+      expect(page).to have_text("Something went wrong while obtaining Let's Encrypt certificate.")
+
+      click_on('Retry')
+
+      expect(page).to have_text("GitLab is obtaining a Let's Encrypt SSL certificate for this domain. This process can take some time. Please try again later.")
+    end
+  end
+
   shared_examples 'user sees private keys only for user provided certificate' do
     shared_examples 'user do not see private key' do
       it 'user do not see private key' do