Wrong error message on pg <= 15 when creating role with `bypassrls`

[steve-chavez]

Problem

$ nix-shell

$ supautils-with-pg-15 psql -U privileged_role

postgres=> create user "prisma" with password 'custom_password' bypassrls createdb;
CREATE ROLE
postgres=> create user "prisma" with password 'custom_password' bypassrls createdb;
2025-03-03 16:59:27.034 -05 [18949] ERROR:  must be superuser to create bypassrls users
2025-03-03 16:59:27.034 -05 [18949] STATEMENT:  create user "prisma" with password 'custom_password' bypassrls createdb;
ERROR:  must be superuser to create bypassrls users

It should say:

ERROR:  42710: role "prisma" already exists