dynamodbstreams describe-stream shows stream not found but the stream is there in list-streams

Steps to recreate:
1. create dynamodb table, 
```
aws dynamodb create-table --table-name MusicCollection --attribute-definitions AttributeName=Artist,AttributeType=S AttributeName=SongTitle,AttributeType=S --key-schema AttributeName=Artist,KeyType=HASH AttributeName=SongTitle,KeyType=RANGE --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5 --endpoint http://localhost:4569
```

2. add stream
```
aws dynamodb update-table --table-name MusicCollection --stream-specification StreamEnabled=true,StreamViewType=NEW_IMAGE --endpoint http://localhost:4569
{
    "TableDescription": {
        "TableArn": "arn:aws:dynamodb:eu-central-1:000000000000:table/MusicCollection", 
        "AttributeDefinitions": [
            {
                "AttributeName": "Artist", 
                "AttributeType": "S"
            }, 
            {
                "AttributeName": "SongTitle", 
                "AttributeType": "S"
            }
        ], 
        "ProvisionedThroughput": {
            "NumberOfDecreasesToday": 0, 
            "WriteCapacityUnits": 5, 
            "LastIncreaseDateTime": 0.0, 
            "ReadCapacityUnits": 5, 
            "LastDecreaseDateTime": 0.0
        }, 
        "TableSizeBytes": 0, 
        "TableName": "MusicCollection", 
        "TableStatus": "ACTIVE", 
        "StreamSpecification": {
            "StreamViewType": "NEW_IMAGE", 
            "StreamEnabled": true
        }, 
        "LatestStreamLabel": "2019-09-21T10:47:14.246", 
        "KeySchema": [
            {
                "KeyType": "HASH", 
                "AttributeName": "Artist"
            }, 
            {
                "KeyType": "RANGE", 
                "AttributeName": "SongTitle"
            }
        ], 
        "ItemCount": 0, 
        "CreationDateTime": 1569062831.736, 
        "LatestStreamArn": "arn:aws:dynamodb:eu-central-1:000000000000:table/MusicCollection/stream/2019-09-21T10:47:14.246"
    }
}
```
3. Note LatestStreamARN from output ```"LatestStreamArn": "arn:aws:dynamodb:eu-central-1:000000000000:table/MusicCollection/stream/2019-09-21T10:47:14.246"```

4. List streams:
```
aws dynamodbstreams list-streams --endpoint http://localhost:4570                                                                                                                  
{
    "LastEvaluatedStreamArn": "TODO", 
    "Streams": [
        {
            "TableName": "MusicCollection", 
            "StreamArn": "arn:aws:dynamodb:eu-central-1:000000000000:table/MusicCollection/stream/2019-09-21T10:47:16", 
            "StreamLabel": "TODO"
        }
    ]
}
```
5. Compare StreamARN to step 3.

Expected behavior: they should match (AWS dynamodb/streams behavior)
inner_request = request.get(key)
                        if inner_request:
                            existing_items.append(find_existing_item(inner_request, table_name))
            ProxyListenerDynamoDB.thread_local.existing_items = existing_items
        elif action == '%s.TransactWriteItems' % ACTION_PREFIX:
            existing_items = []
            for item in data['TransactItems']:
                for key in ['Put', 'Update', 'Delete']:
                    inner_item = item.get(key)
                    if inner_item:
                        existing_items.append(find_existing_item(inner_item))
            ProxyListenerDynamoDB.thread_local.existing_items = existing_items
        elif action == '%s.UpdateTimeToLive' % ACTION_PREFIX:
            
            response = Response()
            response.status_code = 200
            self._table_ttl_map[data['TableName']] = {
                'AttributeName': data['TimeToLiveSpecification']['AttributeName'],
                'Status': data['TimeToLiveSpecification']['Enabled']
            }
            response._content = json.dumps({'TimeToLiveSpecification': data['TimeToLiveSpecification']})
            fix_headers_for_updated_response(response)
            return response
        elif action == '%s.DescribeTimeToLive' % ACTION_PREFIX:
            response = Response()
            response.status_code = 200
            if data['TableName'] in self._table_ttl_map:
                if self._table_ttl_map[data['TableName']]['Status']:
                    ttl_status = 'ENABLED'
                else: