Extract EE-specific lines from issues controller

app/controllers/projects/issues_controller.rb

@@ -9,12 +9,25 @@ class Projects::IssuesController < Projects::ApplicationController
   include IssuesCalendar
   include SpammableActions
 
-  prepend_before_action :authenticate_user!, only: [:new]
+  def self.authenticate_user_only_actions
+    %i[new]
+  end
+
+  def self.issue_except_actions
+    %i[index calendar new create bulk_update]
+  end
+
+  def self.set_issuables_index_only_actions
+    %i[index calendar]
+  end
+
+  prepend_before_action :authenticate_user!, only: authenticate_user_only_actions
 
   before_action :whitelist_query_limiting, only: [:create, :create_merge_request, :move, :bulk_update]
   before_action :check_issues_available!
-  before_action :issue, except: [:index, :calendar, :new, :create, :bulk_update]
-  before_action :set_issuables_index, only: [:index, :calendar]
+  before_action :issue, except: issue_except_actions
+
+  before_action :set_issuables_index, only: set_issuables_index_only_actions
 
   # Allow write(create) issue
   before_action :authorize_create_issue!, only: [:new, :create]