Send more specific emails when SM subscription cannot auto-renew
Problem
Follow up from Avoid speculation of overages in SM auto-renew... (#6098 - closed) and this MR comment https://gitlab.com/gitlab-org/customers-gitlab-com/-/merge_requests/6934#note_1330430610
Customer might be confused about why their SM subscription cannot auto-renew, because the current email is generic.
Proposal
Create 2 new emails to send to the customer in case their SM subscription cannot auto-renew for the following reasons:
- Customer is on Cloud Licensing and they have overages.
- You are using our Cloud Licensing system, you have seat overages, and we have been unable to charge you for them automatically.
- Customer is not on Cloud Licensing.
- You are not using our Cloud Licensing system, and we could not determine whether you have unpaid seat overages for your instance.
Proposed email text
TBD