More controller specs (#2561)

* Add render_views in more places

* Delegate methods from account to user with allow nil true, so that admin accounts show view renders when missing a user

* Use actual account instances in authorize follow controller spec

spec/controllers/media_controller_spec.rb

@@ -3,6 +3,8 @@
 require 'rails_helper'
 
 describe MediaController do
+  render_views
+
   describe '#show' do
     it 'redirects to the file url when attached to a status' do
       status = Fabricate(:status)