Remove unused asset host logic from GfmPipeline and EmojiFilter spec

lib/banzai/pipeline/gfm_pipeline.rb

@@ -44,11 +44,7 @@ module Banzai
       def self.transform_context(context)
         context[:only_path] = true unless context.key?(:only_path)
 
-        context.merge(
-          # EmojiFilter
-          asset_host: Gitlab::Application.config.asset_host,
-          asset_root: Gitlab.config.gitlab.base_url
-        )
+        context
       end
     end
   end

spec/lib/banzai/filter/emoji_filter_spec.rb

@@ -3,15 +3,6 @@ require 'spec_helper'
 describe Banzai::Filter::EmojiFilter do
   include FilterSpecHelper
 
-  before do
-    @original_asset_host = ActionController::Base.asset_host
-    ActionController::Base.asset_host = 'https://foo.com'
-  end
-
-  after do
-    ActionController::Base.asset_host = @original_asset_host
-  end
-
   it 'replaces supported name emoji' do
     doc = filter('<p>:heart:</p>')
     expect(doc.css('gl-emoji').first.text).to eq '❤'