UX: Change admin plugins list to follow UI guidelines (#28478)

This commit introduces a little bit of duplication
since the old plugin UIs not using the new plugin show
page look different from ones like AI and Gamification
which have been converted. We can use the new admin
header component on the plugins list, but for the other
pages we are manually rendering a breadcrumb trail and
the list of plugin tabs.

Over time as we convert more plugins to use the new UI
guidelines and show page we can get rid of this duplication.

spec/system/page_objects/components/d_toggle_switch.rb

@@ -17,6 +17,17 @@ module PageObjects
         actionbuilder = page.driver.browser.action # workaround zero height button
         actionbuilder.click(component).perform
       end
+
+      def checked?
+        find(@context).has_css?(".d-toggle-switch__checkbox[aria-checked=\"true\"]", visible: false)
+      end
+
+      def unchecked?
+        find(@context).has_css?(
+          ".d-toggle-switch__checkbox[aria-checked=\"false\"]",
+          visible: false,
+        )
+      end
     end
   end
 end

spec/system/page_objects/pages/admin_plugins_list.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module PageObjects
+  module Pages
+    class AdminPluginsList < PageObjects::Pages::Base
+      def visit
+        page.visit("/admin/plugins")
+        self
+      end
+
+      def find_plugin(plugin)
+        find(plugin_row_selector(plugin))
+      end
+
+      def plugin_row_selector(plugin)
+        ".admin-plugins-list .admin-plugins-list__row[data-plugin-name=\"#{plugin}\"]"
+      end
+
+      def has_plugin_tab?(plugin)
+        page.has_css?(plugin_nav_tab_selector(plugin))
+      end
+
+      def plugin_nav_tab_selector(plugin)
+        ".admin-nav-submenu__tabs .admin-plugin-tab-nav-item[data-plugin-nav-tab-id=\"#{plugin}\"]"
+      end
+    end
+  end
+end