### What?
If you query with all locales using the `'all'` value for locales, the
`req.locale` value is `'all'` but the type definition only contains the
available locales.
### Why?
The `CustomPayloadRequestProperties.locale` property was only being
typed as `TypedLocale` and was not extending `'all'.`
### How?
Extends type all to the locale type definition in req
Fixes#10244