Make migrate_ui a dependency

It might be a good idea to make migrate_ui a dependency of commerce_migrate_ubercart. As it is, I can enable commerce_migrate_ubercart and then get to it's UI by going to admin/content/migrate/ubercart_migration_options. Once I've entered the db connection info, the config tab remains at admin/content, but I can't do anything else because the migrate ui is missing. I know it's a bit of an edge case, but it confused me until I realized I hadn't enabled migrate_ui