when ddns-send-updates set to false kea-dhcp6 save incorrect lease

Scenario:

• server is configured with two subnets in shared-network, both has just two addresses in pool
• client gets a address from subnet A (has "ddns-send-updates": true) and include fqdn - all ok.
• client gets a address from subnet A (has "ddns-send-updates": true) and DOES NOT include fqdn - all ok.
• client gets a address from subnet B (has "ddns-send-updates": false) and DOES NOT include fqdn - all ok.
• client gets a address from subnet B (has "ddns-send-updates": false) and include fqdn - all is NOT ok.
• kea-dhcp6 responds correctly, does NOT send updates to DNS but saves incorrect lease:

{'arguments': {'duid': '00:03:00:01:11:11:11:11:11:11'},
 'command': 'lease6-get-by-duid'}
[192.168.51.3] sudo: rm -f command_file
{
  "arguments": {
    "leases": [
      {
        "cltt": 1608201895,
        "duid": "00:03:00:01:11:11:11:11:11:11",
        "fqdn-fwd": true,
        "fqdn-rev": true,
        "hostname": "xyz.com.",
        "hw-address": "11:11:11:11:11:11",
        "iaid": 11,
        "ip-address": "2001:db8:b::11",
        "preferred-lft": 3000,
        "state": 0,
        "subnet-id": 2,
        "type": "IA_NA",
        "valid-lft": 4000
      }
    ]
  },
  "result": 0,
  "text": "1 IPv6 lease(s) found."
}

both fields "fqdn-fwd": true, and "fqdn-rev": true, are incorrect should be false

Forge tests:

• tests/dhcpv6/kea_only/control_channel/test_lease_get_by.py::test_control_channel_lease6_get_by