Add basic end-to-end test for admin moderation interface (#29424)

spec/support/stories/profile_stories.rb

@@ -21,6 +21,12 @@ module ProfileStories
     click_on I18n.t('auth.login')
   end
 
+  def as_a_logged_in_admin
+    # This is a bit awkward, but this avoids code duplication.
+    as_a_logged_in_user
+    bob.update!(role: UserRole.find_by!(name: 'Admin'))
+  end
+
   def with_alice_as_local_user
     @alice_bio = '@alice and @bob are fictional characters commonly used as' \
                  'placeholder names in #cryptology, as well as #science and' \

spec/support/streaming_server_manager.rb

@@ -109,6 +109,9 @@ RSpec.configure do |config|
       # Also needs to be set per-example here because of the database cleaner.
       Setting.registrations_mode = 'open'
 
+      # Load seeds so we have the default roles otherwise cleared by `DatabaseCleaner`
+      Rails.application.load_seed
+
       example.run
     end