FIX: Improvements to like button for archived topics (#17951)

* FIX: Do not allow to remove like if topic is archived

* FIX: Always show like button

The like button used to be hidden if the topic was archived and it had
no likes. This commit changes that to always show the like button, but
with a not-allowed cursor if the topic is archived.

spec/serializers/post_serializer_spec.rb

@@ -55,6 +55,14 @@ RSpec.describe PostSerializer do
 
       expect(notify_user_action).to eq(nil)
     end
+
+    it "shows like for archived topics even if user cannot act" do
+      post = Fabricate(:post)
+      post.topic.update!(archived: true)
+
+      serializer = PostSerializer.new(post, scope: Guardian.new(actor), root: false)
+      expect(serializer.as_json[:actions_summary].map { |a| a[:id] }).to include(PostActionType.types[:like])
+    end
   end
 
   context "with a post with reviewable content" do