agent/functional_tests: remove attribute check for subnet and vpc id's when task eni is not enabled
agent/functional_tests: remove attribute check for subnet and vpc id's when task eni is not enabled

swipely/amazon-ecs-agent,swipely/amazon-ecs-agent,aws/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,aws/amazon-ecs-agent,swipely/amazon-ecs-agent,aws/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,swipely/amazon-ecs-agent,aws/amazon-ecs-agent