Refs #37678 - Update evr migration to use DSL

db/migrate/20240624121212_katello_recreate_evr_constructs.rb

@@ -1,14 +1,9 @@
 class KatelloRecreateEvrConstructs < ActiveRecord::Migration[6.1]
-  def change
-    count = select_value <<~SQL
-      SELECT count(*) FROM pg_extension WHERE extname = 'evr';
-    SQL
-    if count.to_i == 0
+  def up
+    if !extension_enabled?('evr')
       return
     else
-      execute <<~SQL
-        DROP EXTENSION evr CASCADE;
-      SQL
+      disable_extension('evr')
 
       execute <<~SQL
               create type evr_array_item as (
@@ -154,6 +149,10 @@ def change
       create_trigger :evr_update_trigger_katello_rpms, on: :katello_rpms
       create_trigger :evr_insert_trigger_katello_installed_packages, on: :katello_installed_packages
       create_trigger :evr_update_trigger_katello_installed_packages, on: :katello_installed_packages
-    end
+     end
+  end
+
+  def down
+    fail ActiveRecord::IrreversibleMigration
   end
 end