Provide account emails in add-on reports

### Required Terms

- [X] I agree to follow this project's [Code of Conduct](https://github.com/heroku/roadmap/blob/main/CODE_OF_CONDUCT.md)
- [X] I have read and accept the [Salesforce Program Agreement](https://www.salesforce.com/company/program-agreement/)

### What service(s) is this request for?

_No response_

### Tell us about what you're trying to solve. What challenges are you facing?

Heroku reports for add-ons like Redis Cloud (https://elements.heroku.com/addons/rediscloud) list users with a heroku_id like app12345678@heroku.com instead of the account email. This makes it impossible for us to create any outreach to our joint customers. Please add the actual account email to the add-on reports.