Fix HTTP 200 response code on paths to remote accounts that don't exist (#40341)

app/controllers/remote_accounts_controller.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class RemoteAccountsController < HomeController
+  before_action :require_resource_exists!
+
+  private
+
+  def require_resource_exists!
+    # The page should still render normally, but the HTTP code should be modified
+    response.status = 404 if permalink_redirector.object.nil?
+  end
+end