refactor result generation

app/mailers/user_mailer.rb

@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
 class UserMailer < ApplicationMailer
-  def invitation_email(user)
-    @current_account = user.account
+  def invitation_email(user, invited_by: nil)
+    @current_account = invited_by&.account || user.account
     @user = user
     @token = @user.send(:set_reset_password_token)