fix(drizzle): generate the locale enum with its actual db name

[EugenieF]

Fixes #17736.

What

generate:db-schema declared the locale enum as pgEnum('enum__locales', …), but the adapter creates that type in Postgres as _locales — enum__locales is only the key in the adapter's enums map:

https://github.com/payloadcms/payload/blob/main/packages/drizzle/src/postgres/init.ts#L22-L27

So every _locale column in a generated schema referenced a type that does not exist in the database. Under push: false the generated file is never executed, so nothing surfaced it.

How

addEnum() already assumed name === db name, and that holds for its only other caller — columnToCodeConverter passes column.enumName, which is a real type name. Rather than change that contract, this adds an optional dbName defaulting to name, so only the locale call site behaves differently.

The exported const keeps the name enum__locales, because columnToCodeConverter.ts#L17 emits enum__locales(…) as the column builder. Only the first argument to pgEnum changes.

Fixture

test/relationships/payload-generated-schema.ts is the one committed fixture that contained the old name; it is updated here. The other two generated-schema fixtures under test/ are not localized and contain no locale enum.

That one-line fixture change is exactly what regenerating produces — the emitted string is deterministic — but I could not run the repo's test suite locally to confirm, so CI is the real check on that file.

Verifying

Before this change, in any localized Postgres project:

SELECT DISTINCT udt_name FROM information_schema.columns
WHERE table_schema = 'public' AND column_name = '_locale';
-- _locales

SELECT typname FROM pg_type WHERE typname = 'enum__locales';
-- 0 rows

while the generated schema declared enum__locales.