DEV: Make all admins TL4 in tests (#25435)

Make admins TL4 by default in tests, foregoing the need to call refresh_auto_groups on them.

spec/serializers/topic_view_details_serializer_spec.rb

@@ -36,7 +36,7 @@ RSpec.describe TopicViewDetailsSerializer do
     before { SiteSetting.can_permanently_delete = true }
 
     it "is true for admins" do
-      admin = Fabricate(:admin, refresh_auto_groups: true)
+      admin = Fabricate(:admin)
 
       serializer = described_class.new(TopicView.new(post.topic, admin), scope: Guardian.new(admin))
       expect(serializer.as_json.dig(:topic_view_details, :can_permanently_delete)).to eq(true)

spec/serializers/topic_view_serializer_spec.rb

@@ -14,7 +14,7 @@ RSpec.describe TopicViewSerializer do
   fab!(:topic)
   fab!(:user) { Fabricate(:user, refresh_auto_groups: true) }
   fab!(:user_2) { Fabricate(:user) }
-  fab!(:admin) { Fabricate(:admin, refresh_auto_groups: true) }
+  fab!(:admin)
 
   describe "#featured_link and #featured_link_root_domain" do
     fab!(:featured_link) { "http://meta.discourse.org" }