fix: validates password and confirm password on the server (#7410)

Fixes https://github.com/payloadcms/payload/issues/7380

Adjusts how the password/confirm-password fields are validated. Moves
validation to the server, adds them to a custom schema under the schema
path `${collectionSlug}.auth` for auth enabled collections.

packages/ui/src/forms/useField/index.tsx

@@ -220,6 +220,7 @@ export const useField = <T,>(options: Options): FieldType<T> => {
       user,
       validate,
       field?.rows,
+      field?.valid,
     ],
   )