Normally S3 objects in localstack can be accessed via `http://localhost:4572/bucket/key`.

However, if the object is 7 MBs or larger, attempting to access it via this URL will result in a 403 error. Objects any smaller are retrieved as expected.

(Possibly related: Lambda response size is limited to 6MB. Perhaps that is being used by accident?)
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:
                    ttl_status = 'DISABLED'
                response._content = json.dumps({
                    'TimeToLiveDescription': {
                        'AttributeName': self._table_ttl_map[data['TableName']]['AttributeName'],