PDExclude example in kea6/all-keys.json is invalid

Using the pool which contains the "excluded-prefix" and "excluded-prefix-len" fields found in all-keys.json would result in

DHCP6_INIT_FAIL failed to initialize Kea server: configuration error using file '/etc/kea-dhcp6.conf': Excluded prefix (48) must be longer than the delegated prefix length (64

which, mind you, is also missing a bracket at the end.