DEV: convert grant badge modal to component API (#23378)

* DEV: convert grant-badge to use component modal API
* DEV: add system test for grant badge modal happy path

spec/system/page_objects/modals/badge.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module PageObjects
+  module Modals
+    class Badge < PageObjects::Pages::Base
+      GRANTABLE_BADGES_DROPDOWN = ".select-kit"
+
+      def modal
+        find(".grant-badge-modal")
+      end
+      def select_badge(badge_name)
+        within(modal) do
+          grantable_badges_dropdown.expand
+          grantable_badges_dropdown.select_row_by_name(badge_name)
+        end
+      end
+
+      def grant
+        within(modal) { find(".modal-footer .btn").click }
+      end
+
+      def has_success_flash_visible?
+        within(modal) { has_css?(".alert-success") }
+      end
+
+      def grantable_badges_dropdown
+        @grantable_badges_dropdown ||=
+          PageObjects::Components::SelectKit.new(GRANTABLE_BADGES_DROPDOWN)
+      end
+    end
+  end
+end