FEATURE: Allow showing only experiments on "What's new?" (#31347)

This commit allows admins to filter the list of feature
feed items on the "What's new?" page to _only_ show experiments.

This is useful to both find existing experiments they may have
enabled, and to get a better overview of new ones they would
like to try.

This will eventually not be required when we build a dedicated
config page for experiments.

spec/system/admin_dashboard_new_features_spec.rb

@@ -51,14 +51,14 @@ describe "Admin New Features Page", type: :system do
 
     new_features_page.visit
 
-    within find(".admin-config-area-card:first-child") do
+    within find(".admin-config-area-card[data-new-features-group='November 2023']") do
       expect(new_features_page).to have_screenshot
       expect(new_features_page).to have_learn_more_link
       expect(new_features_page).to have_no_emoji
       expect(new_features_page).to have_date("November 2023")
     end
 
-    within find(".admin-config-area-card:last-child") do
+    within find(".admin-config-area-card[data-new-features-group='August 2023']") do
       expect(new_features_page).to have_screenshot
       expect(new_features_page).to have_learn_more_link
       expect(new_features_page).to have_no_emoji
@@ -155,6 +155,45 @@ describe "Admin New Features Page", type: :system do
     expect(new_features_page).to have_no_experimental_text
   end
 
+  it "allows filtering to only show experimental items" do
+    DiscourseUpdates.stubs(:new_features).returns(
+      [
+        {
+          "id" => 7,
+          "user_id" => 1,
+          "emoji" => "😍",
+          "title" => "New feature",
+          "description" => "New feature description",
+          "link" => "https://meta.discourse.org",
+          "tier" => [],
+          "discourse_version" => "",
+          "created_at" => "2023-11-10T02:52:41.462Z",
+          "updated_at" => "2023-11-10T04:28:47.020Z",
+          "experiment_setting" => "experimental_form_templates",
+          "experiment_enabled" => true,
+        },
+        {
+          "id" => 8,
+          "user_id" => 1,
+          "emoji" => "🥹",
+          "title" => "Non experimental feature",
+          "description" => "Cool description",
+          "link" => "https://meta.discourse.org",
+          "tier" => [],
+          "discourse_version" => "",
+          "created_at" => "2023-11-10T02:52:41.462Z",
+          "updated_at" => "2023-11-10T04:28:47.020Z",
+          "experiment_setting" => nil,
+          "experiment_enabled" => false,
+        },
+      ],
+    )
+    new_features_page.visit
+    new_features_page.toggle_experiments_only
+    expect(new_features_page).to have_experimental_text
+    expect(new_features_page).not_to have_text("Non experimental feature")
+  end
+
   it "displays a new feature indicator on the sidebar and clears it when navigating to what's new" do
     DiscourseUpdates.stubs(:has_unseen_features?).returns(true)
     visit "/admin"

spec/system/page_objects/pages/admin_new_features.rb

@@ -47,6 +47,14 @@ module PageObjects
       def has_no_experimental_text?
         page.has_no_css?(".admin-new-feature-item__header-experimental")
       end
+
+      def toggle_experiments_only
+        toggle_switch =
+          PageObjects::Components::DToggleSwitch.new(
+            ".admin-new-features__experiments-filter .d-toggle-switch__checkbox",
+          )
+        toggle_switch.toggle
+      end
     end
   end
 end