Apply Layout/LineLength rubocop rule

Note we're excluding a few files:

* Configuration files that weren't generated by us
* Migration files that weren't generated by us
* The Gemfile, since it includes an important comment that must be on
  the same line as the gem declaration
* The Budget::Stats class, since the heading statistics are a mess and
  having shorter lines would require a lot of refactoring

app/controllers/management/users_controller.rb

@@ -24,7 +24,10 @@ class Management::UsersController < Management::BaseController
   end
 
   def erase
-    managed_user.erase(t("management.users.erased_by_manager", manager: current_manager["login"])) if current_manager.present?
+    if current_manager.present?
+      managed_user.erase(t("management.users.erased_by_manager", manager: current_manager["login"]))
+    end
+
     destroy_session
     redirect_to management_document_verifications_path, notice: t("management.users.erased_notice")
   end