Bump @activeadmin/activeadmin from 4.0.0-beta9 to 4.0.0-beta15 and @rails/ujs from 7.1.2 to 7.1.400

Bump @activeadmin/activeadmin from 4.0.0-beta9 to 4.0.0-beta15 and @rails/ujs from 7.1.2 to 7.1.400 #239