NameError when updating Heroky Ruby add-on

### Environment SaaS (https://sentry.io/) ### Steps to Reproduce 1. Have a heroku app with the Sentry heroky add-on using raven-ruby 2. Try to update it to the current version by: 3. Removing the current add-on 4. Follow the steps on this page to configure the current version of ruby: https://devcenter.heroku.com/articles/sentry ### Expected Result User is able to configure the new version ### Actual Result The user gets following error in the Heroku logs ``` "NameError (uninitialized constant Middleware::SentryCatcher::Raven)" ``` Originally reported in this [internal ticket.](https://sentry.zendesk.com/agent/tickets/110855) ### Product Area Settings - Integrations ### Link _No response_ ### DSN _No response_ ### Version _No response_