import in auth example should reflect current package structure

# Documentation Issue

The auth example is mentioned throughout the docs. But the imports dont work anymore. For example here:
https://github.com/payloadcms/payload/blob/05ae957cd5d5a3cd2dba709d3e437d9e47c39ff9/examples/auth/src/collections/hooks/protectRoles.ts#L1

should be changed to latest version and current import a la:

`import type { FieldHook } from 'payload'`