postgres supabase_admin user not created in initial setup

[pweibert]

• [ x] I confirm this is a bug with Supabase, not with my own application.
• [ x] I confirm I have searched the [Docs]

Describe the bug

After upgrading db container to 15.8.1.020 database won't startup correctly complaining that supabase_adming role does not exist.

db starts up correctly with container 15.1.1.78

To Reproduce

1. Delete all postgres database files
2. change db container to 15.8.1.020 & startup your system

System information

I use the container in a kubernetes setup but it looks like a general problem with migrations/db/init-scripts/00000000000000-initial-schema.sql in the most recent commit
ab7f879

the line create user supabase_admin dissapeared (it was present before).

Additional context

This seems to be related to 18836