CDB3-1148 CDB3-1161 LRE LSE make field lotPaymentConfirmation not available for changes if !==null

STR:

1. Go to /api/procedures endpoint
2. Create procedure with next body:

{
    "auctionPeriod": {
        "startDate": "2021-05-30T22:54:00+00:00"
    },
    "sellingMethod": "landRental-english-fast",
    "title": {
        "uk_UA": "test UA title"
    },
    "description": {
        "uk_UA": "test UA description"
    },
    "restrictions": {
        "uk_UA": "test UA restrictions"
    },
    "conditions": {
        "uk_UA": "test UA conditions"
    },
    "accessDetails": {
        "uk_UA": "test UA access details"
    },
    "x_additionalInformation": {
        "uk_UA": "test UA x_additionalInformation"
    },
    "x_documentRequirements": {
        "uk_UA": "test UA x_documentRequirements"
    },
    "leaseType": "landSale",
    "leaseDuration": "P2Y11M",
    "sellingEntity": {
        "identifier": {
            "id": "12345678",
            "scheme": "UA-EDR",
            "legalName": {
                "uk_UA": "asd"
            }
        },
        "address": {
            "streetAddress": {
                "uk_UA": "string"
            },
            "locality": {
                "uk_UA": "string"
            },
            "region": {
                "uk_UA": "Автономна Республіка Крим"
            },
            "postalCode": "string",
            "countryName": {
                "uk_UA": "Україна"
            }
        },
        "contactPoint": {
            "name": {
                "uk_UA": "asd"
            },
            "telephone": "+380123456789",
            "faxNumber": "+380123456789",
            "email": "admin@example.com"
        }
    },
    "lotId": "string",
    "value": {
        "currency": "UAH",
        "amount": 100.0
    },
    "normativeMonetaryValuation": {
        "currency": "UAH",
        "amount": 100.0
    },
    "expertMonetaryValuation": {
        "currency": "UAH",
        "amount": 100.0
    },
    "budgetSpent": {
        "currency": "UAH",
        "amount": 50.0
    },
    "guarantee": {
        "currency": "UAH",
        "amount": 10
    },
    "registrationFee": {
        "currency": "UAH",
        "amount": 5.0
    },
    "minimalStep": {
        "currency": "UAH",
        "amount": 20.0
    },
    "tenderAttempts": 1,
    "items": [
        {
            "description": {
                "uk_UA": "string"
            },
            "address": {
                "streetAddress": {
                    "uk_UA": "string"
                },
                "locality": {
                    "uk_UA": "string"
                },
                "region": {
                    "uk_UA": "Київ"
                },
                "postalCode": "string",
                "countryName": {
                    "uk_UA": "Україна"
                }
            },
            "itemProps": {
                "landArea": 500,
                "cadastralNumber": "123456",
                "ownershipType": "state",
                "encumbrances": "arrest",
                "jointOwnership": "no jointOwnership",
                "utilitiesAvailability": "no utilitiesAvailability"
            }
        }
    ],
    "bankAccounts": [
        {
            "accountType": "payment",
            "accounts": [
                {
                    "bankName": {
                        "uk_UA": "test_bank"
                    },
                    "accountIdentifications": [
                        {
                            "scheme": "UA-accountNumber",
                            "id": "12345"
                        }
                    ],
                    "currency": "UAH"
                }
            ]
        }
    ]
}

3. Wait rectification, make 2 bids, make active
4. Wait auction
5. Activate award
6. Upload doc to contract, patch it
7. Set field 'lotPaymentConfirmation' true value in patch contract endpoint
8. Try to change field value to another

Actual result: can be patched

Expected result: should have validation