fix: graphql missing options route resulting in failed cors preflight checks in production (#8987)

GraphQL currently doesn't pass CORS checks as we don't expose an OPTIONS
endpoint which is used for browser preflights.

Should also fix situations like this
https://github.com/payloadcms/payload/issues/8974

examples/auth/payload/src/app/(payload)/api/graphql/route.ts

@@ -1,6 +1,8 @@
 /* THIS FILE WAS GENERATED AUTOMATICALLY BY PAYLOAD. */
 /* DO NOT MODIFY IT BECAUSE IT COULD BE REWRITTEN AT ANY TIME. */
 import config from '@payload-config'
-import { GRAPHQL_POST } from '@payloadcms/next/routes'
+import { GRAPHQL_POST, REST_OPTIONS } from '@payloadcms/next/routes'
 
 export const POST = GRAPHQL_POST(config)
+
+export const OPTIONS = REST_OPTIONS(config)