refactor(procedure): expose procedure tags on model

app/controllers/administrateurs/procedures_controller.rb

@@ -63,7 +63,7 @@ module Administrateurs
 
     def new
       @procedure ||= Procedure.new(for_individual: true)
-      @existing_tags = get_existing_tags
+      @existing_tags = Procedure.tags
     end
 
     SIGNIFICANT_DOSSIERS_THRESHOLD = 30
@@ -403,11 +403,5 @@ module Administrateurs
     def cloned_from_library?
       params[:from_new_from_existing].present?
     end
-
-    def get_existing_tags
-      unnest = Arel::Nodes::NamedFunction.new('UNNEST', [Procedure.arel_table[:tags]])
-      query = Procedure.select(unnest.as('tags')).distinct.order('tags')
-      Procedure.connection.query(query.to_sql).flatten
-    end
   end
 end

app/models/procedure.rb

@@ -833,6 +833,12 @@ class Procedure < ApplicationRecord
     published_at || created_at
   end
 
+  def self.tags
+    unnest = Arel::Nodes::NamedFunction.new('UNNEST', [self.arel_table[:tags]])
+    query = self.select(unnest.as('tags')).distinct.order('tags')
+    self.connection.query(query.to_sql).flatten
+  end
+
   private
 
   def move_new_children_to_new_parent_coordinate(new_draft)