Error with export openvpn config #808

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

curl -X 'POST'
'https://vpn2.lexact.nl/api/v2/vpn/openvpn/client_export'
-H 'accept: application/json'
-H 'x-api-key: '
-H 'Content-Type: application/json'
-d '{
"id": 0,
"type": "confzip",
"certref": "6952a23bc8eea",
"username": "LexactV3",
"server": 1,
"useaddr": "serveraddr",
"useaddr_hostname": "",
"verifyservercn": "auto",
"blockoutsidedns": false,
"legacy": true,
"silent": false,
"bindmode": "nobind",
"usepkcs11": false,
"pkcs11providers": [],
"pkcs11id": "null",
"usetoken": false,
"usepass": false,
"pass": "",
"p12encryption": "high",
"useproxy": false,
"useproxytype": "http",
"proxyaddr": "",
"proxyport": "",
"useproxypass": "none",
"proxyuser": "",
"proxypass": "",
"advancedoptions": ""
}'

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
To export VPN config

Screenshots or Response
{
"code": 500,
"status": "internal server error",
"response_id": "ENDPOINT_RECEIVED_UNEXPECTED_ERROR",
"message": "in_array(): Argument #2 ($haystack) must be of type array, null given\n#0 /usr/local/pkg/RESTAPI/ModelTraits/OpenVPNClientExportTraits.inc(197): in_array()\n#1 /usr/local/pkg/RESTAPI/Core/Model.inc(1427): RESTAPI\Models\OpenVPNClientExport->validate_legacy()\n#2 /usr/local/pkg/RESTAPI/Core/Model.inc(2067): RESTAPI\Core\Model->validate()\n#3 /usr/local/pkg/RESTAPI/Core/Endpoint.inc(1165): RESTAPI\Core\Model->create()\n#4 /usr/local/pkg/RESTAPI/Core/Endpoint.inc(1071): RESTAPI\Core\Endpoint->post()\n#5 /usr/local/www/api/v2/vpn/openvpn/client_export/index.php(9): RESTAPI\Core\Endpoint->process_request()\n#6 {main}",
"data": []
}

pfSense Version & Package Version:

• pfSense Version: 25.11
• Package Version v2.6.8

Affected Endpoints:

• URL: api/v2/vpn/openvpn/client_export