Disable Metrics/CyclomaticComplexity for Ability.allowed

There's little point to cut that down.

app/models/ability.rb

 class Ability
   class << self
+    # rubocop: disable Metrics/CyclomaticComplexity
     def allowed(user, subject)
       return anonymous_abilities(user, subject) if user.nil?
       return [] unless user.is_a?(User)