This PR fixes and improves a few things around localisation and
fallbackLocale:
- For the REST API `fallbackLocale` and `fallback-locale` are treated
the same for consistency with the Local API
- `fallback: false` in config is now respected, by default results will
not fallback to `defaultLocale` unless this config is true, can also be
overridden by providing an explicit `fallbackLocale` in the request
- locale specific fallbacks will now take priority over `defaultLocale`
unless an explicit fallback is provided
- Fixes types on operations to allow `'none'` as a value for
fallbackLocale
- `fallback` is now true by default if unspecified
Closes https://github.com/payloadcms/payload/issues/8443
f4d526d6e5