PutObjectLegalHold: 500 during switching status to off

[evgeniiz321]

def test_object_lock_get_legal_hold():
    bucket_name = get_new_bucket_name()
    client = get_client()
    client.create_bucket(Bucket=bucket_name, ObjectLockEnabledForBucket=True)
    key = "file1"
    client.put_object(Bucket=bucket_name, Body="abc", Key=key)
    legal_hold = {"Status": "ON"}
    client.put_object_legal_hold(Bucket=bucket_name, Key=key, LegalHold=legal_hold)
    response = client.get_object_legal_hold(Bucket=bucket_name, Key=key)
    assert response["LegalHold"] == legal_hold
    legal_hold_off = {"Status": "OFF"}
    client.put_object_legal_hold(Bucket=bucket_name, Key=key, LegalHold=legal_hold_off)
    response = client.get_object_legal_hold(Bucket=bucket_name, Key=key)
    assert response["LegalHold"] == legal_hold_off

Second put_object_legal_hold with {"Status": "OFF"} results in 500:

2023-10-19T23:19:02.176Z        error   handler/util.go:29      call method     {"status": 500, "request_id": "b58bf023-c37b-4c02-85c1-5baa25a9fa54", "method": "PutObjectLegalHold", "bucket": "yournamehere-q2bte72e99rpkueh-1", "object": "file1", "description": "couldn't head put legal hold", "error": "couldn't delete lock object 'CLdPcpKkxqLuyho2qiBYtDDSFW3x1WdTQ4pjyxW8wBHS' to remove legal hold: mark object removal via connection pool: status: code = 1024 message = incomplete object PUT by placement: could not close object stream: (*putsvc.remoteTarget) could not put object to [/dns4/s01.neofs.devenv/tcp/8080]: finish object stream: status: code = 1024 message = incomplete object PUT by placement: could not close object stream: could not delete objects from tombstone locally: lock object removal"}

If this action is not supported - then NotImplemented should be returned

[smallhive]

After some investigation and @carpawell help I should say, setting OFF with PutObjectLegalHold is not supported by the gate.
This was mentioned in docs but I consider It was not clear enough to understand. In PR #889, I've added a clean error and extended docs.

[carpawell]

Refs nspcc-dev/neofs-contract#247.