tags および tag_names にて論理削除を物理削除に変更 (#416) (#418)

Reviewed-on: #418
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/app/controllers/materials_controller.rb

@@ -237,7 +237,7 @@ class MaterialsController < ApplicationController
   end
 
   def resolve_material_tag! tag_name_raw
-    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
+    tag_name = TagName.find_or_create_by!(name: tag_name_raw)
     tag = tag_name.tag
     tag || Tag.create!(tag_name:, category: :material)
   end