[Policy Bug] DPP Does not supports and operands that are not arrays

[matbmoser]

The DPP does not support and logical operands with one single contraint:

            "odrl:permission": {
                "odrl:action": {
                    "@id": "odrl:use"
                },
                "odrl:constraint": {
                    "odrl:and": {
                        "odrl:leftOperand": {
                            "@id": "test"
                        },
                        "odrl:operator": {
                            "@id": "odrl:eq"
                        },
                        "odrl:rightOperand": "test"
                    }
                }
            },
            "odrl:prohibition": [],
            "odrl:obligation": []

Current Behavior

The policies configured with one constraint do not need a and.
But some people include it, so it could be just one.

Expected Behavior

Detect when a and operand has one specific policy just

Steps To Reproduce

1- Register Policy with and operand and one contraint
2- Configure in the app the and operand
3- Try to access the digital twin registry.